Communication apparatus and communication method

ABSTRACT

Useful data is transmitted to a terminal existing in a transportation vehicle. A communication apparatus installed in the transportation vehicle and configured to transmit the data to the terminal existing in the transportation vehicle includes a data selection unit and an illumination unit. The data selection unit acquires location information indicating a location of the transportation vehicle in which the terminal exists and which is traveling. Based on the acquired location information, the data selection unit selects approaching-location data related to a location ahead of a current location of the transportation vehicle in a traveling direction from a plurality of pieces of data related to the location. The illumination unit transmits, as a modulated light signal, a signal comprising the approaching-location data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application of the PCTInternational Application No. PCT/JP2018/021979 filed on Jun. 8, 2018,which claims the benefit of foreign priority of Japanese patentapplication 2017-129124 filed on Jun. 30, 2017, the contents all ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a communication apparatus and acommunication method.

BACKGROUND ART

For example, as a method for a user to obtain information such asadvertisements in places such as railways, commercial facilities, or thelike, it is known to obtain the information from information displayedon a previously installed display.

As a method for a user to obtain better information, as disclosed in NPL1, a method using a search on the Internet is known.

CITATION LIST Non Patent Literature

NPL 1: “Comparing Internet search engines,” Computer, volume 30, Issue4, April 1997.

SUMMARY OF INVENTION

However, in order to obtain more appropriate information, a user needsto input, for example, a search keyword to a terminal, which causes aproblem that it is difficult to easily obtain the information. On theother hand, when information is obtained from an image displayed on adisplay, the information displayed on the display may not be appropriateinformation the user wants to obtain.

An aspect of the present disclosure provides a communication apparatusand a communication method, which allow a user to more easily obtainmore appropriate information.

In an aspect, the present disclosure provides a communication apparatusinstalled in a transportation vehicle and configured to transmit data toa terminal existing in the transportation vehicle, including a dataselection unit configured to acquire location information associatedwith the transportation vehicle being traveling in which the terminalexists, and, based on the location information, selectapproaching-location data related to a location ahead of a currentlocation of the transportation vehicle in a traveling direction from aplurality of pieces of data related to locations, and an illuminationunit configured to transmit, as a modulated light signal, a signalincluding the approaching-location data.

In an aspect, the present disclosure provides a communication method fortransmitting data from an illumination unit installed in atransportation vehicle to a terminal existing in the transportationvehicle, the method including acquiring location information associatedwith the transportation vehicle being traveling in which the terminalexists, and, based on the location information, selectingapproaching-location data related to a location ahead of a currentlocation of the transportation vehicle in a traveling direction from aplurality of pieces of data related to locations, and transmitting, as amodulated light signal, a signal including the approaching-locationdata.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination of a system, anapparatus, a method, an integrated circuit, a computer program, and astorage medium.

According to an aspect of the present disclosure, a user can obtain moreappropriate information by a simple means.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a principle of line scan sampling.

FIG. 2 is a diagram illustrating an example of an image captured via along exposure time.

FIG. 3 is a diagram illustrating an example of an image captured via ashort exposure time.

FIG. 4A is a diagram for illustrating 4 PPM.

FIG. 4B is a diagram used to illustrate a Manchester coding scheme.

FIG. 5 is a diagram illustrating an example of a configuration of avisible light communication system.

FIG. 6 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 1.

FIG. 7 is a diagram illustrating an example of a frame configurationaccording to Embodiment 1.

FIG. 8 is a diagram illustrating a positional relationship between adevice and a terminal according to Embodiment 2.

FIG. 9 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 3.

FIG. 10 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by a first device according to Embodiment3.

FIG. 11 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by a base station according to Embodiment3.

FIG. 12 is a flow chart illustrating an example of a process performedin a communication system according to Embodiment 3.

FIG. 13 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 4.

FIG. 14 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by a first device according to Embodiment4.

FIG. 15 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by a wireless apparatus of a terminalaccording to Embodiment 4.

FIG. 16 is a flow chart illustrating an example of a process performedin a communication system according to Embodiment 4.

FIG. 17 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 5.

FIG. 18 is a diagram illustrating an example of a frame configuration ofa modulated signal including an SSID transmitted by a third deviceaccording to Embodiment 5.

FIG. 19 is a diagram illustrating an example of a frame configuration ofa modulated signal including an encryption key transmitted by the thirddevice according to Embodiment 5.

FIG. 20 is a flow chart illustrating an example of a process performedin a communication system according to Embodiment 5.

FIG. 21 is a flow chart illustrating another example of a processperformed in a communication system according to Embodiment 5.

FIG. 22 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 6.

FIG. 23 is a flow chart illustrating an example of a process performedin a communication system according to Embodiment 6.

FIG. 24 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 7.

FIG. 25 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by a fifth device according to Embodiment7.

FIG. 26 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by the fifth device according toEmbodiment 7.

FIG. 27 is a diagram illustrating an example of a frame configuration ofa modulated signal transmitted by the fifth device according toEmbodiment 7.

FIG. 28 is a diagram illustrating an example of a frame transmissionmethod by the fifth device according to Embodiment 7.

FIG. 29 is a diagram illustrating an example of a manner of disposing acommunication system in an area according to Embodiment 7.

FIG. 30 is a flow chart illustrating an example of a process performedin a communication system according to Embodiment 7.

FIG. 31 is a diagram illustrating another example of a configuration ofa communication system that performs a visible light communication.

FIG. 32 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 8.

FIG. 33 is a diagram illustrating an example of an advertisementdistribution according to Embodiment 8.

FIG. 34 is a diagram illustrating an example of an advertisementdistribution according to Embodiment 8.

FIG. 35 is a diagram illustrating an example of an advertisementdistribution according to Embodiment 8.

FIG. 36 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 8.

FIG. 37 is a diagram illustrating an example of an advertisementdistribution according to Embodiment 8.

FIG. 38 is a diagram illustrating an example of an advertisementdistribution according to Embodiment 8.

FIG. 39 is a diagram illustrating an example of an advertisementdistribution according to Embodiment 8.

FIG. 40 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 9.

FIG. 41 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 9.

FIG. 42 is a diagram illustrating an example in which displaying isswitched depending on a manner of moving a terminal according toEmbodiment 10.

FIG. 43 is a diagram illustrating an example in which a movementdirection of a terminal is estimated according to Embodiment 10.

FIG. 44 is a diagram illustrating an example of an apparatus connectionrelated to a method of updating data according to Embodiment 11.

FIG. 45 is a diagram illustrating an example of an advertisement bidsituation according to Embodiment 11.

FIG. 46 is a diagram illustrating an example of an advertisement bidsituation according to Embodiment 11.

FIG. 47 is a diagram illustrating an example of a positional situationof monitors and persons each having a communication apparatus accordingto Embodiment 12.

FIG. 48 is a diagram illustrating another example of a positionalsituation of monitors and persons each having a communication apparatusaccording to Embodiment 12.

FIG. 49 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 13.

FIG. 50 is a diagram illustrating an example of an advertisement bidsituation according to Embodiment 13.

FIG. 51 is a diagram illustrating another example of an advertisementbid situation according to Embodiment 13.

FIG. 52 is a diagram illustrating another example of an advertisementbid situation according to Embodiment 13.

FIG. 53 is a diagram illustrating another example of an advertisementbid situation according to Embodiment 13.

FIG. 54 is a diagram illustrating an example of a configuration of adata generation apparatus according to Embodiment 14.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are described in detail below withreference to drawings.

[Modulation/Demodulation Method in Visible Light Communication]

In a visible light communication method according to an embodimentdescribed below, a modulated signal is transmitted/received, forexample, as a visible light signal.

First, an outline of the visible light communication method is describedspecifically.

<Line Scan Sampling>

A smartphone, a digital camera, or the like, includes an image sensorsuch as a CMOS (Complementary Metal Oxide Semiconductor) sensor. Animage is captured by a CMOS sensor not such that the whole area of theimage of scenery is captured at the exactly same time but such that anamount of light sensed by the sensor is output on a line-by-line base.Therefore, starting and ending of receiving of light is controlledtaking into account a time necessary for reading such that starting andending of light reception vary in time from line to line. That is, theimage captured by the CMOS sensor has a feature in which many lineshaving a small time lag from each other are superimposed.

The present embodiment provides a visible light communication methodusing the above-described feature of the CMOS sensor, thereby achievinga high-speed visible light signal reception. That is, in the visiblelight communication method, by utilizing the fact that the exposure timevaries slightly from line to line, it is possible to measure theluminance and color of a light source at a plurality of points of timeon a line-by-line basis from one image (captured by the image sensor) asshown in FIG. 1, and thus it is possible to detect a signal modulated ata higher rate than a frame rate.

Hereinafter, this sampling method is referred to as “line scansampling”, and a row of pixels exposed at the same timing is referred toas an “exposure line”.

However, when an image of a light source which flashes at a high rate(pulse lighting) is captured using imaging setting made for a camerafunction (a function of taking a moving image or a still image),flashing of the light source does not cause a stripe pattern to appearalong the exposure lines. Because, in this setting, the exposure time ismuch longer than the flash cycle (pulse width) of the light source, thechange in luminance due to the flashing (a light emission pattern) ofthe light source is averaged, and a change in pixel value betweenexposure lines becomes extremely small and a resultant image hassubstantially uniform luminance as shown in FIG. 2.

On the other hand, as shown in FIG. 3, when the exposure time is set toa value close to the flash cycle of the light source, it is possible toobserve flashing of the light source (the light emission pattern) as achange in luminance of the exposure line.

For example, the exposure line is designed to be parallel to thedirection of the long side of the image sensor. In this case, when theframe rate is set to, by way of example, 30 fps (frames per second),32400 or more samples per second can be obtained for a resolution or asize of 1920×1080, and 64800 or more samples per second can be obtainedfor a resolution or a size of 3840×2160.

<Light Source and Modulation Scheme>

In visible light communication, for example, an LED (Light EmittingDiode) can be used as a transmitter. LEDs are becoming popular aslighting or backlight sources of displays, and can be flashed at highrates.

However, a light source used as a transmitter for visible lightcommunication can not be controlled so as to flash freely for visiblelight communication. If flashing in visible light communication isvisible to human beings, the original function of the light source aslighting is impaired. Therefore, it is required that the transmissionsignal be as bright as possible without flicker being felt by humaneyes.

As a modulation scheme that meets this requirement, for example, thereis a modulation scheme called 4-PPM (4-Pulse Position Modulation). Inthe 4 PPM scheme, 2 bits are represented by four combinations ofbight/dark states of a light source as shown in FIG. 4A. In the 4 PPM,as shown in FIG. 4A, 3 of 4 pulses are in the bright state and 1 of 4pules is in the dark state. Therefore, the average of the brightness(the average luminance) is ¾=75% regardless of signals.

For comparison, a similar scheme called a Manchester coding scheme isshown in FIG. 4B. In the Manchester coding scheme, 1 bit is representedby 2 states, and the modulation efficiency is 50% which is the same asthat of the 4 PPM. However, because 1 of 2 pulses is in a bright stateand the other 1 of 2 is in a dark state, the average luminance is ½=50%.That is, it can be concluded that 4 PPM is more suitable than theManchester coding scheme as a modulation scheme for visible lightcommunication.

<Example of Overall Configuration of Communication System>

As shown in FIG. 5, the communication system that performs visible lightcommunication includes at least a transmitter configured to transmit(emit) a light signal and a receiver configured to receive (sense) alight signal. For example, there are two types of transmitters: variablelight transmitters that change transmission content according to animage or content to be displayed; and fixed light transmitters thatcontinue to transmit fixed transmission content.

The receiver may receive a light signal from the transmitter and, forexample, may obtain related information associated with the light signaland provide it to a user.

The outline of the visible light communication method has been describedabove. The communication method applicable to the light communicationaccording to embodiments described below is not limited to the methoddescribed above. For example, a light emitting unit of the transmittermay transmit data using a plurality of light sources. Furthermore,another communication method may be employed in which a receiver of thereception apparatus may not be an image sensor such as a CMOS but may berealized using a device, such as a photodiode, capable of converting anoptical signal to an electrical signal. In this case, since it is notnecessary to perform sampling using the above-described line scansampling, it is applicable even to a system in which sampling at a rateof more than 32400 per second is required. Furthermore, depending on theapplication, for example, a communication method may be realized usingradio frequency transmission instead of using visible light such asinfrared light, ultraviolet light, or the like.

Embodiment 1

FIG. 6 illustrates an example of a configuration of a device 100 andthat of a terminal 150 according to Embodiment 1.

[Configuration of Device 100]

The device 100 (corresponding to a transmitter for visible lightcommunication) includes a visible light source such as an LED (LightEmitting Diode), lighting, or a light (also referred collectively to asa light source). Hereinafter, the device 100 may also be referred to asthe “first device”.

In the first device 100 in FIG. 6, a transmitter 102 gets, as an inputthereto, information 101 related to a place or a location.Alternatively, information 105 related to time may be input to thetransmitter 102. Information input to the transmitting unit 102 mayinclude both the information 101 related to the place or the locationand the information 105 related to the time.

The transmitter 102 gets, as inputs thereto, the information 101 relatedto the place or the location and/or the information 105 related to thetime and generates a (light) modulated signal 103 based on these inputsignals and outputs the resultant modulated signal 103. The modulatedsignal 103 is transmitted, for example, from a light source 104.

An example of information 101 related to the place or the location isdescribed below.

Example 1

The information 101 related to the place or the location may beinformation on a latitude of a place/location and/or information on alongitude of the place/location. For example, the information 101related to the place or the location may be information indicating“latitude of 45° north and longitude of 135° east”.

Example 2

The information 101 related to the place or the location may beinformation indicating an address. For example, the information 101related to the place or the location may be information indicating“1-1-1 XX-cyo, Chiyoda-ku, Tokyo”.

Example 3

The information 101 related to the place or the location may beinformation related to a building, a facility, or the like. For example,the information 101 related to the place or the location may beinformation indicating “Tokyo Tower”.

Example 4

The information 101 related to the place or the location may beinformation related to a unique place/location of something installed ina building, a facility or the like.

For example, let it be assumed that there are spaces in a parking lotwhere it is allowed to park five cars. In this situation, let A-1 denotea first parking space, let A-2 denote a second parking space, let A-3denote a third parking space, let A-4 denote a fourth parking space, andlet A-5 denote a fifth parking space. In this case, for example,information indicating “A-3” may be employed as the information 101related to the place or the location.

Note that such an example is not limited to the case of parking lots.For example, information related to “an area, a seat, a shop, afacility”, or the like located in a concert facility, a stadium such asa baseball stadium, a soccer stadium, a tennis stadium or the like, onan airplane, in an airport lounge, in a railway facility, in a station,or the like may be employed as the information 101 related to the placeor the location.

Examples of the information 101 related to the place or the locationhave been described above. Note that the method of configuring theinformation 101 related to the place or the location is not limited tothe above example.

[Configuration of Terminal 150]

The terminal 150 (corresponding to the receiver for visible lightcommunication) in FIG. 6 receives the modulated signal 103 transmittedfrom the first device 100.

A light receiver (light receiver) 151 is, for example, an image sensorsuch as a CMOS (Complementary Metal Oxide Semiconductor) sensor, anorganic CMOS sensor, or the like. The light receiver 151 receives lightincluding the modulated signal transmitted from the first device 100,and outputs a reception signal 152.

The reception signal 152 output from the light receiver 151 may be asignal including information of an image or a moving image acquired bythe image sensor, or may be an output signal output from an element thatperforms photoelectric conversion (conversion from light to an electricsignal). In the following description, when it is simply described thatan apparatus at a receiving end receives a modulated signal withoutdescribing a process performed by the light receiver 151, it is assumedthat the light receiver 151 in the apparatus at the receiving endperforms photoelectric conversion (conversion from light to an electricsignal) on the light including the modulated signal thereby obtaining a“signal of an image and/or a moving image” and a “modulated signal fortransmitting information”. However, the method described above is anexample of a method in which the apparatus at the receiving end receivesa modulated signal, and the method of receiving the modulated signal isnot limited to this example.

A receiver 153 receives, as an input thereto, the reception signal 152,and performs processing such as demodulation, error correction decoding,and/or the like on the modulated signal included in the reception signal152 and outputs a result as reception data 154.

A data analysis unit 155 receives, as an input thereto, the receptiondata 154 and analyzes the reception data 154 to estimate, for example,the place/location of the terminal 150, and outputs information 156including at least place information and/or location informationassociated with the terminal 150.

A display 157 receives, as an input thereto, the information 156, anddisplays a place/location of the terminal 150 based on theplace/location information associated with the terminal 150 included inthe information 156.

[Frame Configuration]

FIG. 7 illustrates an example of a frame configuration of a modulatedsignal transmitted by the first device 100.

In FIG. 7, a horizontal axis represents time. The first device 100transmits, for example, a preamble 201, and then transmits a controlinformation symbol 202, a symbol 203 related to place information orlocation information, and a symbol 204 related to time information.

The preamble 201 is a symbol for use by the terminal 150 in, whenreceiving a modulated signal transmitted from the first device 100,performing, for example, signal detection, time synchronization, framesynchronization, and/or the like.

The control information symbol 202 is a symbol including, for example,data indicating a configuration of a modulated signal, an errorcorrection coding scheme being used, a frame configuration and/or thelike.

The symbol 203 related to place information or location information is asymbol including information 101 related to the place or the locationshown in FIG. 6.

Note that a frame may include a symbol other than the symbols 201, 202,and 203. For example, a frame may include a symbol 204 related to timeinformation as shown in FIG. 7. The symbol 204 related to timeinformation includes, for example, information 105 related to the timeat which the first device 100 transmits a modulated signal. The frameconfiguration of the modulated signal transmitted by the first device100 is not limited to that shown in FIG. 7, and the symbols included inthe modulated signal are not limited to those shown in FIG. 7. The framemay include a symbol containing other data/information.

[Effects]

When the first device 100 transmits a modulated signal and the terminal150 receives this modulated signal as described above with referenceFIG. 6 and FIG. 7, effects are obtained as described below.

Visible light is used in transmitting the modulated signal from thefirst device 100, and thus this modulated signal can be received by theterminal 150 only when the location of the terminal 150 is not far fromthe location of the first device 100. Therefore, by obtaining theplace/location information transmitted by the first device 100, theterminal 150 can easily obtain high-accuracy location information(without performing complicated signal processing).

Furthermore, when the first device 100 is installed in a place where itis difficult to receive GPS satellite radio waves, the terminal 150 cansecurely obtain high-accuracy location information by receiving themodulated signal transmitted from the first device 100 even in asituation in which it is difficult to receive radio waves from GPSsatellites.

Embodiment 2

In Embodiment 2, an explanation is given for a case where a plurality offirst devices 100 described in Embodiment 1 exist.

In the present embodiment, for example, as shown in FIG. 8, a device#1-1 301-1 having a configuration similar to that of the first device100 shown in FIG. 6 transmits a modulated signal. A terminal 302 havinga configuration similar to that of the terminal 150 shown in FIG. 6receives the modulated signal transmitted by the device #1-1 301-1, andobtains information related to, for example, a place/location #1-1 andinformation related to time #1-1.

Similarly, a device #1-2 301-2, having the same configuration as that ofthe first device 100 shown in FIG. 6, transmits a modulated signal. Theterminal 302 receives the modulated signal transmitted from the device#1-2 301-2, and obtains, for example, information related to aplace/location #1-2 and the information related to time #1-2.

The terminal 302 can calculate the distance between the device #1-1301-1 and the device #1-2 301-2 shown in FIG. 8 from the informationrelated to the place/location #1-1 and the information related to theplace/location #1-2. The terminal 302 can also calculate the distancebetween the terminal 302 and the device #1-1 301-1 based on theinformation related to the time #1-1 and, for example, the informationrelated to the time at which the terminal 302 receives the modulatedsignal transmitted from the device #1-1 301-1. Similarly, the terminal302 can calculate the distance between the terminal 302 and the device#1-2 301-2 based on the information related to the time #1-2 and, forexample, the information related to the time at which the terminal 302receives the modulated signal transmitted from the device #1-2 301-2.

The terminal 302 can get to know the location of the device #1-1 301-1from the information related to the place/location #1-1. The terminal302 can get to know the location of the device #1-2 301-2 from theinformation related to the place/location #1-2.

Furthermore, the terminal 302 can obtain information indicating a“triangle formed by the device #1-1 301-1, the device #1-2 301-2, andthe terminal 302” from the “distance between the device #1-1 301-1 andthe device #1-2 301-2”, the “distance between the device #1-1 301-1 andthe terminal 302”, and the “distance between the device #1-2 301-2 andthe terminal 302”.

Thus, the terminal 302 can calculate and obtain the high-accuracylocation of the terminal 302 from the “location of the device #1-1301-1”, the “location of the device #1-2 301-2”, and the “triangleformed by the device #1-1 301-1, the device #1-2 301-2, and the terminal302”.

The geodetic survey method used by the terminal 302 to obtainplace/location information is not limited to that described above, butany geodetic survey method may be employed. Examples of geodetic surveymethods include triangulation, traversing, trilateration, leveling, andthe like.

As described above, in the present embodiment, the terminal 302estimates the location of the terminal 302 with high accuracy byobtaining the above-described information from the plurality of devices301 each including a light source that transmits place information.

In the present embodiment, as in the Embodiment 1, when the device 301having the light source that transmits place information is installed ina place where it is difficult to receive GPS satellite radio waves, theterminal 302 can securely obtain high-accuracy location information byreceiving the modulated signal transmitted from the device 301 even in asituation in which it is difficult to receive radio waves from GPSsatellites.

In the above examples, the terminal 302 receives the modulated signaltransmitted from the two devices 301. However, the terminal 302 mayreceive modulated signals transmitted from more than two devices 301 ina similar manner. As the number of devices 301 increases, the accuracyof the location information calculated by the terminal 302 increases.

Embodiment 3

FIG. 9 illustrates an example of a configuration of a device 400, aterminal 450, and a base station 470 (or an AP (access point)) thatcommunicates with the terminal 450 according to Embodiment 3.

The device 400 includes, for example, a visible light source such as anLED, lighting, a light source, or a light. Hereinafter, the device 400may also be referred to as a “first device”.

In the first device 400 shown in FIG. 9, elements similar in operationto those in the first device 100 shown in FIG. 6 are denoted by similarreference numerals. In the terminal 450 shown in FIG. 9, elementssimilar in operation to those in the terminal 150 shown in FIG. 6 aredenoted by similar reference numerals.

In the first device 400 in FIG. 9, a transmitter 102 gets, as inputsthereto, for example, information 101 related to the place or thelocation, information 401-1 related to an SSID (service set identifier)functioning as an identifier identifying the base station 470, andinformation 401-2 related to an access destination. Alternatively,information 105 related to time may be input to the transmitter 102.

The transmitter 102 gets, as inputs thereto, information 101 related tothe place or the location, the information 401-1 related to the SSID,and the information 401-2 related to the access destination, and/orinformation 105 related to the time, and the transmitter 102 generates a(light) modulated signal 103 based on these input signals and outputsthe resultant modulated signal 103. The modulated signal 103 istransmitted, for example, from a light source 104.

Examples of the information 101 related to the place or the locationhave been described above in Embodiment 1, and thus a furtherdescription thereof is omitted.

Next, information 401-1 related to the SSID and information 401-2related to the access destination are described below.

First, the information 401-1 related to the SSID is described.

The information 401-1 related to the SSID is information indicating theSSID of the base station 470 in FIG. 9. In a case where it is determinedin advance that the SSID notified via a light signal is the SSID of asecure base station, the first device 400 can provide, to the terminal450, access to the base station 470 which is a secure accessdestination. This enables the terminal 450 in FIG. 9 to obtaininformation securely from base station 470.

On the other hand, the first device 400 can limit terminals that areallowed to access the base station 470 to those terminals that arelocated within a space in which it is possible to receive a light signaltransmitted (emitted) by the first device 400.

When the terminal 450 receives a light signal transmitted in apredetermined scheme, the terminal 450 may determine that the notifiedSSID is an SSID of a secure base station. The terminal 450 may perform aseparate process of determining whether the notified SSID is secure ornot. For example, the first device 400 may transmit a light signalincluding a predetermined identifier, and the terminal 450 may determinewhether the notified SSID is an SSID of a secure base station or notbased on the received identifier. Alternatively, the terminal 450 maynot perform the process of determining whether the base station issecure or not, but a user may select a high-security first device 400based on the nature of visible light. The terminal 450 then may receivea light signal from this first device 400 and may obtain the SSID of thehigh-security base station.

Although only the base station 470 is shown as a base station in FIG. 9,there may be one or more other base stations (or APs) in addition to thebase station 470. Also, in such a case, the terminal 450 may access thebase station 470 using the SSID obtained from the first device 400 toacquire information.

Next, information 401-2 related to the access destination is described.

The access destination information 401-2 is information related to anaccess destination to which the terminal 450 is to access to acquireinformation after the terminal 450 accesses the base station 470. Aspecific example of an operation according to the present embodimentwill be described later.

The SSID information 401-1 and the access destination information 401-2have been described above.

The terminal 450 receives the modulated signal 103 transmitted from thefirst device 400.

The light receiver 151 is, for example, an image sensor such as a CMOSsensor or an organic CMOS sensor. The light receiver 151 receives lightincluding the modulated signal transmitted from the first device 400,and outputs a reception signal 152.

The receiver 153 receives, as an input thereto, the reception signal 152received by the light receiver 151, and performs processing such asdemodulation/error correction decoding on the modulated signal includedin the reception signal 152 and outputs a result as reception data 154.

The reception data 154 is input to the data analysis unit 155. The dataanalysis unit 155 estimates, for example, the place/location of theterminal 450 from the reception data 154. The data analysis unit 155outputs information 156 including at least place/location informationassociated with the terminal 450, information 451 related to the SSID,and information 452 related to the access destination.

The display 157 receives, as inputs thereto, the information 156including the place/location information related to the terminal 450,the information 451 related to the SSID, and the information 452 relatedto the access destination, and the display 157 displays, for example,the place/location of the terminal 450, the SSID of the communicationdestination to be accessed by the wireless apparatus 453 disposed in theterminal 450, and/or the access destination (hereinafter, thisdisplaying will be referred to as “first displaying”).

After performing the first displaying, the wireless apparatus 453receives, as inputs thereto, the information 451 related to the SSID andthe information 452 related to the access destination. Based on theinformation 451 related to the SSID, the wireless apparatus 453 connectsto a communication destination by using, for example, a radio wave. Inthe case shown in FIG. 9, the wireless apparatus 453 is connected to thebase station 470.

The wireless apparatus 453 generates a modulated signal from the dataincluding the information related to the access destination based on theinformation 452 related to the access destination, and transmits theresultant modulated signal to the base station 470 using, for example, aradio wave.

In FIG. 9, the base station 470 which is a communication counterpart ofthe terminal 450 receives the modulated signal transmitted from thewireless apparatus 453 of the terminal 450.

Then, the base station 470 performs processing such as demodulation,error correction decoding on the received modulated signal and outputsreception data 471 including the information on the access destinationtransmitted from the terminal 450. The base station 470 accesses adesired access destination via a network based on the access destinationinformation, and obtains, for example, desired information 472 from theaccessed destination. The base station 470 receives the desiredinformation 472 as an input thereto, generates a modulated signal fromthe desired information 472, and transmits the resultant modulatedsignal to the terminal 450 (the wireless apparatus 453) using, forexample, a radio wave.

The wireless apparatus 453 of the terminal 450 receives the modulatedsignal transmitted from the base station 470, and performs processingsuch as demodulation/error correction decoding, and/or the like therebyobtaining desired information 472.

Let it be assumed by way example that the desired information 472includes information about a map, a map of a building/floor guide, a mapof a facility/floor guide, a map of a parking lot/floor guide,“area/seat/store/facility” located in a concertfacility/stadium/airplane/airport lounge/railway/station etc.

The display 157 receives, as inputs thereto, information 454 includingthe desired information 472, information 156 including at least theplace/location information related to the terminal 450, and information451 related to the SSID, and the display 157 performs the firstdisplaying and further displaying such that the location of the terminal450 is mapped on the displayed information such as the map, the floorguide, facility information, seat information, or shop information basedon the desired information 472 and the information 156 including atleast information on the place/location of the terminal 450.

FIG. 10 illustrates an example of a frame configuration of a modulatedsignal transmitted by the first device 400 shown in FIG. 9. In FIG. 10,a horizontal axis represents time. In FIG. 10, symbols similar, ininformation conveyed thereby, to symbols shown in FIG. 7 are denoted bysimilar reference numerals, and a further description thereof isomitted.

The first device 400 transmits, for example, a preamble 201, and thentransmits a control information symbol 202, a symbol 203 related toplace information or location information, and a symbol 204 related totime information, and, in addition, a symbol 600-1 related to the SSIDand a symbol 600-2 related to the access destination.

The symbol 600-1 related to the SSID is a symbol for transmitting theinformation 401-1 related to the SSID in FIG. 9, and the symbol 600-2related to the access destination is a symbol for transmitting theinformation 401-2 related to the access destination in FIG. 9. The frameshown in FIG. 10 may include a symbol other than the symbols describedin FIG. 10. Note that the frame configuration, including the order oftransmitting symbols, is not limited to the configuration shown in FIG.10.

FIG. 11 illustrates an example of a frame configuration of a modulatedsignal transmitted by the base station 470 shown in FIG. 9. In FIG. 11,a horizontal axis represents time.

As shown in FIG. 11, the base station 470 transmits, for example, apreamble 701, and then transmits a control information symbol 702 and aninformation symbol 703.

The preamble 701 is a symbol used by the terminal 450 in, when receivinga modulated signal transmitted by the base station 470, performing, forexample, signal detection, time synchronization, frame synchronization,frequency synchronization, frequency offset estimation, and the/or like.

The control information symbol 702 is, for example, a symbol includingdata such as information related to an error correction coding schemeand modulation scheme used in generating the modulated signal,information related to a frame configuration, and/or the like. Thewireless apparatus 453 of the terminal 450 performs processing such asdemodulation or the like on the modulated signal based on theinformation represented by the control information symbol 702.

The information symbol 703 is a symbol for transmitting information. Inthe present embodiment, the information symbol 703 is a symbol fortransmitting the desired information 472 described above.

The base station 470 shown in FIG. 9 may transmit a frame including asymbol other than the symbols shown in FIG. 11. For example, the basestation 470 may transmit a frame including a pilot symbol (a referencesymbol) in the middle of the information symbol 703, or the like. Theframe configuration, including the order of transmitting symbols, is notlimited to the configuration shown in FIG. 11. In FIG. 11, a pluralityof symbols may exist in a direction along the frequency axis. That is,in FIG. 11, symbols may exist at a plurality of frequencies (a pluralityof carriers).

For example, in a method, the modulated signal in the frameconfiguration shown in FIG. 10 may be transmitted by the first device400, for example, repeatedly at regular intervals. This makes itpossible for a plurality of terminals 400 to perform the operation asdescribed above.

FIG. 12 is a flow chart illustrating an example of a process performedby the “first device 400”, the “terminal 450”, and the “base station470” describe above with reference to FIG. 9.

First, the first device 400 transmits a modulated signal in the frameconfiguration shown in FIG. 10 (ST801).

The terminal 450 receives the modulated signal transmitted from thefirst device 400, and estimates the place/location of the terminal 450(ST802).

The terminal 450 receives the modulated signal transmitted from thefirst device 400, and also detects the SSID of the base station 470 thatthe terminal 450 is to access (ST803).

The terminal 450 transmits, to the base station 470 using a radio wave,a modulated signal including data including information 452 related toan access destination therefrom to obtain information such as a map(ST804).

The base station 470 receives the modulated signal transmitted from theterminal 450 and obtains access destination information. The basestation 470 accesses a desired access destination via a network, andobtains desired information such as a map (information to be transmittedto the terminal 450) (ST805).

The base station 470 transmits a modulated signal including the desiredinformation such as the acquired map to the terminal 450 using, forexample, a radio wave (ST806).

The terminal 450 receives the modulated signal transmitted from the basestation 470 and obtains information such as a map. The terminal 450 thenperforms displaying based on the information such as the map and thealready obtained information related to the place/location of theterminal 450 (ST807).

Note that the terminal 450 may store the map (nearby information) andthe location information in a storage unit (not shown) of the terminal450 such that a user is allowed to access the information stored in thestorage unit when the user of the terminal 450 wants to access. Thismakes it possible for the user to more conveniently use the map (nearbyinformation) and the location information.

As described above, visible light is used in transmitting the modulatedsignal from the first device 400, and thus this modulated signal can bereceived by the terminal 450 only when the terminal 450 is locatedwithin a range from the location of the first device 400 in which it ispossible to receive the light signal. Therefore, by obtaining theplace/location information transmitted by the first device 400, theterminal 450 can easily obtain high-accuracy location information(without performing complicated signal processing).

Furthermore, when the first device 400 is installed in a place where itis difficult to receive GPS satellite radio waves, the terminal 450 cansecurely obtain high-accuracy location information by receiving themodulated signal transmitted from the first device 400 even in asituation in which it is difficult to receive radio waves from GPSsatellites.

Furthermore, based on the SSID information transmitted from the firstdevice 400, the terminal 450 may connect with the base station (or theAP) 470 to obtain information thereby making it possible for theterminal 450 to securely obtain information. This is because, when theterminal 450 obtains information from the modulated signal of visiblelight, use of the visual light makes it possible for the user to easilyrecognize, via a visual inspection or the like, the first device 400that transmits the modulated signal and to easily determine whether theinformation source is secure or not. In contrast, for example, in a casewhere an SSID is acquired from a modulated signal of a radio wavetransmitted via a wireless LAN, it is difficult for a user to determinea device from which the radio wave is received. Thus, from the point ofview of ensuring the security of information, visible lightcommunication is more suitable for acquiring an SSID than wireless LANcommunication.

A plurality of signals may be further input to the wireless apparatus453 of the terminal 450 in FIG. 9. For example, a control signal forcontrolling the wireless apparatus 453 and information to be transmittedto the base station 470 may be input to the wireless apparatus 453. Inthis case, by way of example, the wireless apparatus 453 may startcommunication based on the control signal. As described above, in thepresent embodiment, the configuration of the first device is not limitedto the configuration of the first device 400 in FIG. 9, theconfiguration of the terminal is not limited to the configuration of theterminal 450 of FIG. 9, and the connection destination to be connectedby the base station and the configuration of the destination device arenot limited to the connection destination to be connected by the basestation 470 and the configuration of the destination device shown inFIG. 9.

Furthermore, although in the example shown in FIG. 9, the base station470 is the only base station existing there, there may be a plurality of(secure) base stations (or APs) which can be accessed by the terminal450. In this case, the symbol related to the SSID transmitted by thefirst device 400 shown in FIG. 9 may include information indicating therespective SSIDs of the plurality of base stations (or APs). In thiscase, the display 157 of the terminal 450 in FIG. 9 displays informationindicating access destinations (in the above-described “firstdisplaying”) including a list of SSIDs of the plurality of base stationsand/or a list of a plurality of access destinations. The terminal 450 inFIG. 9 may select one or more base stations to which a wirelessconnection is actually made based on the information indicating theSSIDs of the plurality of base stations (or APs) (that is, the terminal450 may connect to the plurality of base stations at the same time).

For example, let it be assumed that there are three base stations 470.Herein, let the three base stations 470 be respectively referred to as abase station #A, a base station #B, and a base station #C. Furthermore,let it be assumed that the SSID of the base station #A is “abcdef”, theSSID of the base station #B is “ghijk”, and the SSID of the base station#C is “pqrstu”. In this case, the symbol 600-1 related to the SSIDdescribed in the modulated signal transmitted from the first device 400in the frame configuration shown in FIG. 10 includes informationindicating that the SSID of the base station #A is “abcdef”, SSID of thebase station #B is “ghijk” and the SSID of the base station #C is“pqrstu”. The terminal 450 in FIG. 9 receives the symbol 600-1 relatedto the SSID, and selects one or more base stations 470 to be actuallywirelessly connected based on the information indicating that the SSIDof the base station #A is “abcdef”, SSID of the base station #B is“ghijk” and the SSID of the base station #C is “pqrstu”.

Embodiment 4

FIG. 13 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 4.

The communication system shown in FIG. 13 includes, for example, adevice 1000, a terminal 1050, and a base station (or an AP) 470 thatcommunicates with the terminal 1050.

The device 1000 includes, for example, a visible light source such as anLED, lighting, a light source, and a light (hereinafter, referred to asa light source 104). Hereinafter, the device 1000 may also be referredto as a “second device” according to the present embodiment.

In the second device 1000 shown in FIG. 13, elements similar inoperation to those in the first device 100 shown in FIG. 6 are denotedby similar reference numerals. In the terminal 1050 shown in FIG. 13,elements similar in operation to those in the terminal 150 shown in FIG.6 are denoted by similar reference numerals. Note that it is assumedthat communication between the wireless apparatus 453 of the terminal1050 and the base station 470 shown in FIG. 13 is performed using, forexample, radio waves.

In the second device 1000 in FIG. 13, a transmitter 102 gets, as inputsthereto, information 1001-1 related to an SSID, information 1001-2related to an encryption key, and data 1002, and the second device 1000generates a (light) modulated signal 103 based on these input signalsand outputs the resultant modulated signal 103. The modulated signal 103is transmitted, for example, from a light source 104.

Next, information 1001-1 related to the SSID and information 1001-2related to the encryption key are described below.

First, the information 1001-1 related to the SSID is described.

The information 1001-1 related to the SSID is information indicating theSSID of the base station 470 in FIG. 13. By way of example, the basestation 470 transmits a modulated signal to the terminal 1050 via aradio wave, and receives a modulated signal from the terminal 105 via aradio wave. That is, the second device 1000 can provide, to the terminal1050, access to the base station 470, which is a secure accessdestination. Thus, the terminal 1050 shown in FIG. 13 can securelyobtain information from the base station 470.

On the other hand, the second device 1000 can limit terminals allowed toaccess the base station 470 to those terminals that are located within aspace in which it is possible to receive a light signal transmitted(emitted) by the second device 1000.

When the terminal 1050 receives a light signal transmitted in apredetermined scheme, the terminal 1050 may determine that the notifiedSSID is an SSID of a secure base station. The terminal 1050 may performa separate process of determining whether the notified SSID is secure ornot. For example, the second device 1000 may transmit a light signalincluding a predetermined identifier, and the terminal 1050 maydetermine whether the notified SSID is an SSID of a secure base stationor not based on the received identifier.

Although only the base station 470 is shown in FIG. 13, there may be oneor more other base stations (or APs) in addition to the base station470. Also, in such a case, the terminal 1050 may access the base station470 using the SSID obtained from the second device 1000 to acquireinformation.

Next, the information 1001-2 related to the encryption key is described.

The information 1001-2 related to the encryption key is informationrelated to an encryption key required for the terminal 1050 tocommunicate with the base station 470. By acquiring the information1001-2 related to the encryption key from the second device 1000, itbecomes possible for the terminal 1050 to perform encryptedcommunication with the base station 470.

The information 1001-1 related to the SSID and the information 1001-2related to the encryption key have been described above.

The terminal 1050 in FIG. 13 receives a modulated signal transmittedfrom the second device 1000. In the terminal 1050 shown in FIG. 13,elements similar in operation to those in the terminal 150 shown in FIG.6 or the terminal 450 shown in FIG. 9 are denoted by similar referencenumerals.

The light receiver 151 of the terminal 1050 is, for example, an imagesensor such as a CMOS sensor or an organic CMOS sensor. The lightreceiver 151 receives light including the modulated signal transmittedfrom the second device 1000, and outputs a reception signal 152.

The receiver 153 receives, as an input thereto, the reception signal 152received by the light receiver 151, and performs processing such asdemodulation/error correction decoding on the modulated signal includedin the reception signal 152 and outputs a result as reception data 154.

The data analysis unit 155 receives, as an input thereto, the receptiondata 154, and outputs, based on the reception data 154, for example,information 1051 related to an SSID of a base station that is to beconnected and information 1052 related to an encryption key forcommunicating with the base station that is to be connected. Encryptionschemes for use in a wireless LAN (Local Area Network) include, forexample, WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access),WPA2 (Wi-Fi Protected Access 2) (PSK (Pre-Shared Key) mode, EAP(Extended Authentication Protocol) mode). Note that the encryptionschemes are not limited to the examples described above.

The display 157 receives, as inputs thereto, the information 1051 on theSSID and the information 1052 on the encryption key, and displays, forexample, an SSID of a communication counterpart to be accessed by thewireless apparatus 453 of the terminal 1050 and an encryption key (thisdisplaying is referred to as “first displaying” according to the presentembodiment).

For example, after the first displaying, the wireless apparatus 453receives, as inputs thereto, the SSID information 1051 and theencryption key information 1052, and establishes a connection with thebase station 470 (for example, a radio wave is used in the connection).In this situation, in a case where the base station 470 alsocommunicates with the wireless apparatus 453 of the terminal 1050, thebase station 470 transmits a modulated signal using, for example, aradio wave.

Thereafter, the wireless apparatus 453 receives, as inputs thereto, thedata 1053 and the control signal 1054, and modulates the data 1053according to the control indicated by the control signal 1054 andtransmits a result as the modulated signal using a radio wave.

Then, for example, the base station 470 performs data transmission (471)to a network and data reception (472) from the network. Thereafter, forexample, the base station 470 transmits the modulated signal to theterminal 1050 using a radio wave.

The wireless apparatus 453 in the terminal 1050 performs processing suchas demodulation, error correction decoding, and/or the like on themodulated signal received via the radio wave thereby acquiring receptiondata 1056. The display 157 performs displaying based on the receptiondata 1056.

FIG. 14 illustrates an example of a frame configuration of the modulatedsignal transmitted by the second device 1000 shown in FIG. 13. In FIG.14, a horizontal axis represents time. In FIG. 14, symbols similar tothose shown in FIG. 7 or FIG. 10 are denoted by similar referencenumerals, and a description thereof is omitted.

A symbol 600-1 related to the SSD is a symbol for transmitting theinformation 1001-1 related to the SSID shown in FIG. 13, and a symbol1101 related to the encryption key is a symbol for transmitting theinformation 1001-2 related to the encryption key shown in FIG. 13. Adata symbol 1102 is a symbol for transmitting the data 1002 shown inFIG. 13.

The second device 1000 transmits a preamble 201, a control informationsymbol 202, a symbol 600-1 related to the SSID, a symbol 1101 related tothe encryption key, and a data symbol 1102. The second device 1000 maytransmit a frame including a symbol other than the symbols shown in FIG.14. The frame configuration, including the order of transmittingsymbols, is not limited to the configuration shown in FIG. 14.

FIG. 15 illustrates an example of a frame configuration of a modulatedsignal transmitted by the wireless apparatus 453 included in theterminal 1050 shown in FIG. 13. In FIG. 15, a horizontal axis representstime.

As shown in FIG. 15, the wireless apparatus 453 included in the terminal1050 transmits, for example, a preamble 1201, and then transmits acontrol information symbol 1202 and an information symbol 1203.

The preamble 1201 is a symbol for use by the base station 470 in, whenreceiving the modulated signal transmitted from the wireless apparatus453 of the terminal 1050, performing, for example, signal detection,time synchronization, frame synchronization, a frequencysynchronization, frequency offset estimation and/or the like.

The control information symbol 1202 is, for example, a symbol includingdata such as information related to an error correction coding schemeand a modulation scheme used in generating a modulated signal,information related to a frame configuration, information related to atransmission scheme, and/or the like. The base station 470 performsprocessing such as demodulation on the modulated signal or the likebased on the information included in the control information symbol1202.

The information symbol 1203 is a symbol for the wireless apparatus 453of the terminal 1050 to transmit data.

The wireless apparatus 453 of the terminal 1050 may transmit a frameincluding a symbol other than the symbols shown in FIG. 15. For example,the wireless apparatus 453 may transmit a frame including a pilot symbol(a reference symbol) in the middle of the information symbol 1203, orthe like. The frame configuration, including the order of transmittingsymbols, is not limited to the configuration shown in FIG. 15. In FIG.15, a plurality of symbols may exist in a direction along the frequencyaxis. That is, in FIG. 15, symbols may exist at a plurality offrequencies (a plurality of carriers). In Embodiment 3, when thewireless apparatus 453 included in the terminal 450 shown in FIG. 9transmits a modulated signal, the frame configuration shown in FIG. 15may be used.

The frame configuration of the modulated signal transmitted by basestation 470 according to the present embodiment is the same as the frameconfiguration according to Embodiment 3 described above with referenceto FIG. 11. That is, as shown in FIG. 11, the base station 470transmits, for example, a preamble 701, and then transmits a controlinformation symbol 702 and an information symbol 703.

The preamble 701 is a symbol for use by the wireless apparatus 453 ofthe terminal 1050 in, when receiving a modulated signal transmitted bythe base station 470, performing, for example, signal detection, timesynchronization, frame synchronization, frequency synchronization,frequency offset estimation, and the/or like.

The control information symbol 702 is, for example, a symbol includingdata such as information related to an error correction coding schemeand a modulation scheme used in generating a modulated signal,information related to a frame configuration, information related to atransmission scheme, and/or the like. The wireless apparatus 453 of theterminal 1050 performs processing such as demodulation or the like onthe modulated signal based on the information represented by the controlinformation symbol 702.

The information symbol 703 is a symbol used by the base station 470 totransmit data.

The base station 470 shown in FIG. 13 may transmit a frame including asymbol other than the symbols shown in FIG. 11. For example, the basestation 470 may transmit a frame including a pilot symbol (a referencesymbol) in the middle of the information symbol 703, or the like. Theframe configuration, including the order of transmitting symbols, is notlimited to the configuration shown in FIG. 11. In FIG. 11, a pluralityof symbols may exist in a direction along the frequency axis. That is,in FIG. 11, symbols may exist at a plurality of frequencies (a pluralityof carriers).

For example, in a method, the modulated signal in the frameconfiguration shown in FIG. 14 may be transmitted, for example, by thesecond device 1000, for example, repeatedly at regular intervals. Thismakes it possible for a plurality of terminals 1050 to perform theoperation as described above.

FIG. 16 is a flow chart illustrating an example of a process performedby the “second device 1000”, the “terminal 1050”, and the “base station470” described above with reference to FIG. 13.

First, the second device 1000 transmits a modulated signal in the frameconfiguration shown in FIG. 14 (ST1301).

The terminal 1050 receives the modulated signal transmitted from thesecond device 1000, and detects the SSID of the base station 470 thatthe terminal 1050 is to access (ST1302).

The terminal 1050 also acquires an encryption key used for communicationwith the base station 470 to be accessed by the terminal 1050 (ST1303).

The terminal 1050 then connects to the base station 470 using a radiowave (ST1304). When the terminal 1050 receives a response from the basestation 470, the connection with the base station 470 is completed(ST1305).

The terminal 1050 then transmits connection destination information tothe base station 470 using a radio wave (ST1306).

The base station 470 obtains information to be transmitted to theterminal 1050 from a network (ST1307).

The base station 470 transmits the obtained information to the terminal1050 using a radio wave. The terminal 1050 obtains this information(ST1308). The terminal 1050 may obtain necessary information from thenetwork via the base station 470, for example, when necessary.

As described above, the terminal 1050 connects to the base station 470based on the information on the SSID and the information on theencryption key transmitted from the second device 1000, and thus theterminal 1050 can securely acquire information via the base station 470guaranteed to be secure. This is because when the terminal 1050 obtainsinformation from a modulated signal of visible light, use of the visiblelight allows the user to easily determine whether the information sourceis secure or not. In contrast, for example, in a case where an SSID isacquired from a modulated signal of a radio wave transmitted via awireless LAN, it is difficult for a user to determine a device fromwhich the radio wave is received. Thus, from the point of view ofensuring the security of information, visible light communication ismore suitable for acquiring an SSID than wireless LAN communication.

In the present embodiment described above, by way of example, the seconddevice 1000 transmits the information on the encryption key. However,for example, when the base station 470 does not perform communicationencrypted using an encryption key, the second device 1000 may transmitonly the information on the SSID without transmitting the information onthe encryption key. In this case, the operation may be performed in asimilar manner as described above except that part of the operationrelated to the encryption key described above is not performed.

Note that the configuration of the second device is not limited to thespecific configuration of the second device 1000 shown in FIG. 13. Theconfiguration of the terminal is not limited to the specificconfiguration of the terminal 1050 shown in FIG. 13. The connectiondestination to which the base station is connected is not limited to theconnection destination to which the base station 470 shown in FIG. 13 isconnected, and the configuration of the connection destination device isnot limited to the configuration of the connection destination deviceshown in FIG. 13.

Furthermore, although in the example shown in FIG. 13, the base station470 is the only base station existing there, there may be a plurality of(secure) base stations (or APs) which can be accessed by the terminal1050. Note that the plurality of base stations and the terminal 1050transmit and receive modulated signals using radio waves. In this case,the symbol related to the SSID transmitted by the second device 1000shown in FIG. 13 may include information indicating the respective SSIDsof the plurality of base stations (or APs). In this case, the display157 of the terminal 1050 in FIG. 13 displays information indicatingaccess destinations including a list of SSIDs of the plurality of basestations and/or a list of a plurality of access destinations. The symbolrelated to the encryption key transmitted by the second device 1000shown in FIG. 13 may include information indicating the respectiveencryption keys for connecting to the respective base stations (or APs).The terminal 1050 in FIG. 13 may select one or more base stations to beactually connected wirelessly (for example, using radio waves) based onthe information on the SSIDs of the plurality of base stations and theinformation on the encryption keys (that is, the terminal 1050 may beconnected to a plurality of base stations at the same time).

For example, let it be assumed that there are three base stations 470.Herein, let the three base stations 470 be respectively referred to as abase station #A, a base station #B, and a base station #C. Furthermore,let it be assumed that the SSID of the base station #A is “abcdef”, theSSID of the base station #B is “ghijk”, and the SSID of the base station#C is “pqrstu”. Let it be further assumed that an encryption key forconnecting to the base station #A is “123”, an encryption key forconnecting to the base station #B is “456”, and an encryption key forconnecting to the base station #C is “789”.

In this case, the symbol 600-1 related to the SSID described in themodulated signal transmitted from the second device 1000 in the frameconfiguration shown in FIG. 14 includes information indicating the SSIDof the base station #A is “abcdef”, SSID of the base station #B is“ghijk” and the SSID of the base station #C is “pqrstu”. The symbol 1101related to the encryption key in the frame configuration shown in FIG.14 includes information indicating that the encryption key forconnecting to the base station #A is “123”, the encryption key forconnecting to the base station #B is “456”, and the encryption key forconnecting to the base station #C is “789”.

The terminal 1050 in FIG. 13 receives the symbol 600-1 related to theSSID thereby obtaining information indicating that the SSID of the basestation #A is “abcdef”, the SSID of the base station #B is “ghijk” andthe SSID of the base station #C is “pqrstu”. The terminal 1050 alsoreceives the symbol 1101 related to the encryption key thereby obtaininginformation indicating that the encryption key for connecting to thebase station #A is “123”, the encryption key for connecting to the basestation #B is “456” and the encryption key for connecting to the basestation #C is “789”. The terminal 1050 selects one or more base stationsto be actually wirelessly connected (for example, via a radio wave)based on these pieces of information, and connects to the selected oneor more base stations.

By performing setting of the base station 470 to be accessed by theterminal 1050 using a light source such as an LED according to thepresent embodiment, it becomes unnecessary for the modulated signal forwireless communication transmitted by the terminal 1050 to have aspecial setting mode for a procedure to establish a wirelesscommunication connection between the terminal 1050 and the base station470. It also becomes unnecessary to provide, in the modulated signaltransmitted by the terminal 1050, a special setting mode for a procedureto make a wireless communication connection between the terminal 1050and the base station 470. Thus, according to the present embodiment, itis possible to improve the data transmission efficiency of wirelesscommunication.

As described above, the encryption key may be an encryption key for theSSID for the wireless LAN, or may be an encryption key for limiting theconnection mode, the service mode, the connection range of the network,and/or the like. That is, an encryption key may be introduced forimposing some restriction.

Embodiment 5

FIG. 17 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 5.

The communication system shown in FIG. 17 includes, for example, devices1400A and 1400B, a terminal 1050, and a base station (or an AP) 470 thatcommunicates with the terminal 1050.

The devices 1400A and 1400B each include, for example, a visible lightsource such as an LED, lighting, a light source, and a light(hereinafter referred to as light sources 1406-1 and 1406-2).Hereinafter, the device 1400A will be referred to as a “third device”according to the present embodiment, and the device 1400B will bereferred to as a “fourth device” according to the present embodiment.

In the terminal 1050 shown in FIG. 17, elements that operate in similarmanners to those in the terminal 150 shown in FIG. 6 or the terminal1050 shown in FIG. 13 are denoted by similar reference numerals. In thebase station (the AP) shown in FIG. 17, elements that operate in similarmanners to those in the base station 470 shown in FIG. 9 are denoted bythe same reference numerals as those used in FIG. 9. Note that it isassumed that communication between the wireless apparatus 453 of theterminal 1050 and the base station 470 shown in FIG. 17 is performedusing, for example, radio waves.

In the third device 1400A in FIG. 17, a transmitter 1404-1 gets, asinputs thereto, information 1401-1 related to an SSID and data 1402-1,and generates a (light) modulated signal 1405-1 based on these inputsignals and outputs the resultant modulated signal 1405-1. The modulatedsignal 1405-1 is transmitted, for example, from the light source 1406-1.

In the fourth device 1400B in FIG. 17, a transmitter 1404-2 gets, asinputs thereto, information 1403-2 related to an encryption key and data1402-2, and generates a (light) modulated signal 1405-2 based on theseinput signals and outputs the resultant modulated signal 1405-2. Themodulated signal 1405-2 is transmitted, for example, from the lightsource 1406-2.

Next, information 1401-1 related to the SSID and information 1403-2related to the encryption key are described below.

First, the information 1401-1 related to the SSID is described.

The information 1401-1 related to the SSID is information indicating theSSID of the base station 470 in FIG. 17. That is, the third device 1400Acan provide, to the terminal 1050, access to the base station 470 whichis a secure access destination via a radio wave. Thus, the terminal 1050shown in FIG. 17 can securely obtain information from the base station470.

When the terminal 1050 receives a light signal transmitted in apredetermined scheme, the terminal 1050 may determine that the notifiedSSID is an SSID of a secure base station. The terminal 1050 may performa separate process of determining whether the notified SSID is secure ornot. For example, the third device 1400A may transmit a light signalincluding a predetermined identifier, and the terminal 1050 maydetermine whether the notified SSID is an SSID of a secure base stationor not based on the received identifier.

Although only the base station 470 is shown in FIG. 17, there may be oneor more other base stations (or APs) in addition to the base station470. Also, in such a case, the terminal 1050 may access the base station470 using the SSID obtained from the third device 1400A and theencryption key acquired from the fourth device 1400B to acquireinformation.

Next, the information 1403-2 related to the encryption key is described.

The encryption key information 1403-2 is information related to anencryption key required for the terminal 1050 to communicate with thebase station 470 via a radio wave. By acquiring the information 1403-2related to the encryption key from the fourth device 1400B, it becomespossible for the terminal 1050 to perform encrypted communication withthe base station 470.

The information 1401-1 related to the SSID and the information 1403-2related to the encryption key have been described above.

The terminal 1050 in FIG. 17 receives a modulated signal transmittedfrom the third device 1400A.

The light receiver 151 of the terminal 1050 is, for example, an imagesensor such as a CMOS sensor or an organic CMOS sensor. The lightreceiver 151 receives light including the modulated signal transmittedfrom the third device 1400A, and outputs a reception signal 152.

The receiver 153 receives, as an input thereto, the reception signal 152received by the light receiver 151, and performs processing such asdemodulation/error correction decoding on the modulated signal includedin the reception signal 152 and outputs a result as reception data 154.

The data analysis unit 155 receives, as an input thereto, the receptiondata 154, and outputs, based on the reception data, for example,information 1051 related to the SSID of the base station that is to be aconnection destination. Thus, the wireless apparatus 453 obtains, fromthe information 1051 relates to the SSID, the information on the SSID ofthe base station 470 that the wireless apparatus 453 is to connect tovia a radio wave.

The terminal 1050 in FIG. 17 receives the modulated signal transmittedfrom the fourth device 1400B.

The light receiver 151 of the terminal 1050 is, for example, an imagesensor such as a CMOS sensor or an organic CMOS sensor. The lightreceiver 151 receives light including the modulated signal transmittedfrom the fourth device 1400B, and outputs a reception signal 152.

The receiver 153 receives, as an input thereto, the reception signal 152received by the light receiver 151, and performs processing such asdemodulation/error correction decoding on the modulated signal includedin the reception signal 152 and outputs a result as reception data 154.

The data analysis unit 155 receives, as an input thereto, the receptiondata 154, and outputs, based on the reception data, for example,information 1052 related to an encryption key for communicating with abase station that is to be a connection destination. Encryption schemesfor use in a wireless LAN (Local Area Network) include, for example, WEP(Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), WPA2 (Wi-FiProtected Access 2) (PSK (Pre-Shared Key) mode, EAP (ExtendedAuthentication Protocol) mode). Note that the encryption schemes are notlimited to the examples described above.

Thus, from the information 1052 relates to the encryption key forcommunicating with the base station to which the wireless apparatus 453is to connect (for example, via a radio wave), the wireless apparatus453 in the terminal 1050 obtains information on the encryption key forcommunicating with the base station 470 to which the wireless apparatus453 is to be connected.

The display 157 receives, as inputs thereto, the information 1051 on theSSID and the information 1052 on the encryption key, and displays, forexample, an SSID of a communication counterpart to be accessed by thewireless apparatus 453 of the terminal 1050 and an encryption key (thisdisplaying is referred to as “first displaying” according to the presentembodiment).

For example, after the first displaying, the wireless apparatus 453receives, as inputs thereto, the SSID information 1051 and theencryption key information 1052, and establishes a radio-wave connectionwith the base station 470. In this situation, in a case where the basestation 470 also communicates with the wireless apparatus 453 of theterminal 1050, the base station 470 transmits a modulated signal using,for example, a radio wave.

Thereafter, the wireless apparatus 453 receives, as inputs thereto, thedata 1053 and the control signal 1054, and modulates the data 1053according to the control indicated by the control signal 1054 andtransmits a result as the modulated signal using a radio wave.

Then, for example, the base station 470 performs data transmission (471)to a network and data reception (472) from the network. Thereafter, forexample, the base station 470 transmits the modulated signal to theterminal 1050 using a radio wave.

The wireless apparatus 453 in the terminal 1050 performs processing suchas demodulation, error correction decoding, and/or the like on themodulated signal received via the radio wave thereby acquiring receptiondata 1056. The display 157 performs displaying based on the receptiondata 1056.

FIG. 18 illustrates an example of a frame configuration of a modulatedsignal transmitted by the third device 1400A shown in FIG. 17. In FIG.18, a horizontal axis represents time. In FIG. 18, symbols similar tothose in FIG. 2, FIG. 10, or FIG. 14 are denoted by similar referencenumerals, and a description thereof is omitted.

A symbol 600-1 related to an SSID is a symbol for transmitting theinformation 1401-1 related to the SSID shown in FIG. 17. A data symbol1102 is a symbol for transmitting the data 1402-1.

The third device 1400A transmits a preamble 201, a control informationsymbol 202, a symbol 600-1 related to an SSID, and a data symbol 1102.The third device 1400A may transmit a frame including a symbol otherthan the symbols shown in FIG. 18. The frame configuration, includingthe order of transmitting symbols, is not limited to the configurationshown in FIG. 18.

FIG. 19 illustrates an example of a frame configuration of a modulatedsignal transmitted by the fourth device 1400B shown in FIG. 17. In FIG.19, a horizontal axis represents time. In FIG. 19, symbols similar tothose shown in FIG. 7 or FIG. 14 are denoted by the same referencenumerals, and a description thereof is omitted.

A symbol 1101 related to an encryption key is a symbol for transmittingthe information 1403-2 related to the encryption key shown in FIG. 17. Adata symbol 1102 is a symbol for transmitting the data 1402-2.

The fourth device 1400B transmits a preamble 201, a control informationsymbol 202, a symbol 1101 related to an encryption key, and a datasymbol 1102. The fourth device 1400B shown in FIG. 17 may transmit aframe including a symbol other than the symbols shown in FIG. 19. Theframe configuration, including the order of transmitting symbols, is notlimited to the configuration shown in FIG. 19.

The frame configuration of the modulated signal transmitted by wirelessapparatus 453 according to the present embodiment is the same as theframe configuration according to Embodiment 4 described above withreference to FIG. 15. That is, as shown in FIG. 15, the wirelessapparatus 453 included in the terminal 1050 transmits, for example, apreamble 1201, and then transmits a control information symbol 1202 andan information symbol 1203.

The preamble 1201 is a symbol for use by the base station (or the AP)470 in, when receiving the modulated signal transmitted from thewireless apparatus 453 of the terminal 1050 shown in FIG. 17,performing, for example, signal detection, time synchronization, framesynchronization, a frequency synchronization, frequency offsetestimation and/or the like.

The control information symbol 1202 is, for example, a symbol includingdata such as information related to an error correction coding schemeand modulation scheme used in generating a modulated signal, informationrelated to a frame configuration, and information related to atransmission scheme, and/or the like. The base station 470 performsprocessing such as demodulation on the modulated signal or the likebased on the information included in the control information symbol1202.

The information symbol 1203 is a symbol for the wireless apparatus 453of the terminal 1050 to transmit data.

The wireless apparatus 453 of the terminal 1050 shown in FIG. 17 maytransmit a frame including a symbol other than the symbols shown in FIG.15. For example, the wireless apparatus 453 may transmit a frameincluding a pilot symbol (a reference symbol) in the middle of theinformation symbol 1203, or the like. The frame configuration, includingthe order of transmitting symbols, is not limited to the configurationshown in FIG. 15. In FIG. 15, a plurality of symbols may exist in adirection along the frequency axis. That is, in FIG. 15, symbols mayexist at a plurality of frequencies (a plurality of carriers).

The frame configuration of the modulated signal transmitted by basestation 470 according to the present embodiment is the same as the frameconfiguration according to Embodiment 3 described above with referenceto FIG. 11. That is, as shown in FIG. 11, the base station 470transmits, for example, a preamble 701, and then transmits a controlinformation symbol 702 and an information symbol 703.

The preamble 701 is a symbol for use by the wireless apparatus 453 ofthe terminal 1050 shown in FIG. 17 in, when receiving the modulatedsignal transmitted by the base station 470, performing, for example,signal detection, time synchronization, frame synchronization, frequencysynchronization, frequency offset estimation, and/or the like.

The control information symbol 702 is, for example, a symbol includingdata such as information related to an error correction coding schemeand a modulation scheme used in generating a modulated signal,information related to a frame configuration, information related to atransmission scheme, and/or the like. The wireless apparatus 453 of theterminal 1050 shown in FIG. 17 performs processing such as demodulationor the like on the modulated signal based on the information representedby the control information symbol 702.

The information symbol 703 is a symbol used by the base station 470 inFIG. 17 to transmit data.

The base station 470 shown in FIG. 17 may transmit a frame including asymbol other than the symbols shown in FIG. 11. For example, the basestation 470 may transmit a frame including a pilot symbol (a referencesymbol) in the middle of the information symbol 703, or the like. Theframe configuration, including the order of transmitting symbols, is notlimited to the configuration shown in FIG. 11. In FIG. 11, a pluralityof symbols may exist in a direction along the frequency axis. That is,in FIG. 11, symbols may exist at a plurality of frequencies (a pluralityof carriers).

For example, in a method, the modulated signal in the frameconfiguration shown in FIG. 18 may be transmitted by the third device1400A repeatedly, for example, at regular intervals. This makes itpossible for a plurality of terminals 1050 to perform the operation asdescribed above. Similarly, in a method, the modulated signal in theframe configuration shown in FIG. 19 may be transmitted by the fourthdevice 1400B repeatedly, for example, at regular intervals. This makesit possible for a plurality of terminals 1050 to perform the operationas described above.

FIG. 20 is a flow chart illustrating a first example of processingperformed by the “third device 1400A”, the “fourth device 1400B”, the“terminal 1050”, and the “base station 470” illustrated in FIG. 17. InFIG. 20, elements that operate in similar manners to those shown in FIG.16 are denoted by similar reference numerals.

First, the third device 1400A transmits a modulated signal in the frameconfiguration shown in FIG. 18 (ST1701).

The terminal 1050 receives the modulated signal transmitted from thethird device 1400A, and acquires the SSID of the base station 470 to beaccessed by the terminal 1050 (ST1702).

Next, the fourth device 1400B transmits a modulated signal in the frameconfiguration shown in FIG. 19 (ST1703).

The terminal 1050 receives the modulated signal transmitted from thefourth device 1400B, and acquires the encryption key for use incommunicating with the base station 470 to be accessed by the terminal1050 (ST1704).

The terminal 1050 then connects to the base station 470 using a radiowave (ST1304). When the terminal 1050 receives a response from the basestation 470, the radio-wave connection with the base station 470 iscompleted (ST1305).

The terminal 1050 then transmits connection destination information tothe base station 470 using a radio wave (ST1306).

The base station 470 obtains information to be transmitted to theterminal 1050 from a network (ST1307).

The base station 470 transmits the obtained information to the terminal1050 using a radio wave. The terminal 1050 obtains this information(ST1308). The terminal 1050 may obtain necessary information from thenetwork via the base station 470, for example, when necessary.

FIG. 21 is a flow chart illustrating a second example of processingperformed by the “third device 1400A”, the “fourth device 1400B”, the“terminal 1050”, and the “base station 470” illustrated in FIG. 17. InFIG. 21, elements that operate in similar manners to those shown in FIG.16 are denoted by similar reference numerals.

First, the fourth device 1400B transmits a modulated signal in the frameconfiguration shown in FIG. 19 (ST1801).

The terminal 1050 receives the modulated signal transmitted from thefourth device 1400B, and acquires the encryption key for use incommunicating with the base station 470 to be accessed by the terminal1050 (ST1802).

Next, the third device 1400A transmits a modulated signal in the frameconfiguration shown in FIG. 18 (ST1803).

The terminal 1050 receives the modulated signal transmitted from thethird device 1400A, and acquires the SSID of the base station 470 to beaccessed by the terminal 1050 (ST1804).

The terminal 1050 then connects to the base station 470 using a radiowave (ST1304). When the terminal 1050 receives a response from the basestation 470, the radio-wave connection with the base station 470 iscompleted (ST1305).

The terminal 1050 then transmits connection destination information tothe base station 470 using a radio wave (ST1306).

The base station 470 obtains information to be transmitted to theterminal 1050 from a network (ST1307).

The base station 470 transmits the obtained information to the terminal1050 using a radio wave. The terminal 1050 obtains this information(ST1308). The terminal 1050 may obtain necessary information from thenetwork via the base station 470, for example, when necessary.

As described above, based on the SSID transmitted from the third device1400A and the information on the encryption key transmitted from thefourth device 1400B, the terminal 1050 connects to the base station 470and acquires information. That is, since the device from which theterminal 1050 acquires information on the SSID is different from thedevice from which the information on the encryption key is acquired, theinformation can be securely acquired via the base station 470 whosesecurity is guaranteed. This is because when the terminal 1050 obtainsinformation from a modulated signal of visible light, use of the visiblelight allows the user to easily determine whether the information sourceis secure or not. In contrast, for example, in a case where an SSID isacquired from a modulated signal of a radio wave transmitted via awireless LAN, it is difficult for a user to determine a device fromwhich the radio wave is received. Thus, from the point of view ofensuring the security of information, visible light communication ismore suitable for acquiring an SSID than wireless LAN communication.

In the present embodiment described above, by way of example, the fourthdevice 1400B transmits the information on the encryption key. However,for example, when the base station 470 does not perform communicationencrypted using an encryption key, the information on the encryption keyis not transmitted by the fourth device 1400B. In this case, only theinformation on the SSID may be transmitted by the third device 1400A. Inthis case, the operation may be performed in a similar manner asdescribed above except that part of the operation related to theencryption key described above is not performed.

In the present embodiment, the device (the third device 1400A) thattransmits information related to the SSID is different from the device(the fourth device 1400B) that transmits information related to theencryption key, and thus it becomes possible for the terminal 1050 tomore securely communicate with the base station 470.

Note that the encryption key for use by the terminal 1050 incommunicating with the base station 470 may be changed (for example, inparticular time intervals) such that it becomes impossible for theterminal 1050 having an old encryption key to communicate with the basestation 470. By performing such operation, it is possible to performmore secure communications.

Note that the configurations of the third device and the fourth deviceare not limited to the specific configurations of the third device 1400Aand the fourth device 1400B shown in FIG. 17. The configuration of theterminal is not limited to the specific configuration of the terminal1050 shown in FIG. 17. The connection destination to which the basestation is connected is not limited to the connection destination towhich the base station 470 shown in FIG. 17 is connected, and theconfiguration of the connection destination device is not limited to theconfiguration of the connection destination device shown in FIG. 17.

Furthermore, although in the example shown in FIG. 17, the base station470 is the only base station existing there, there may be a plurality of(secure) base stations (or APs) which can be accessed by the terminal1050. In this case, the symbol related to the SSID transmitted by thethird device 1400A shown in FIG. 17 may include information indicatingthe SSIDs of the respective base stations 470. The symbol related to theencryption key transmitted by the fourth device 1400B shown in FIG. 17may include information on the encryption key used to connect to each ofthe plurality of base stations. In this case, the display 157 of theterminal 1050 in FIG. 17 displays information indicating accessdestinations (in the above-described “first displaying”) including alist of SSIDs of the plurality of base stations and/or a list of aplurality of access destinations. The terminal 1050 in FIG. 17 mayselect one or more base stations to be actually connected wirelesslybased on the information on the SSIDs of the plurality of base stationsand the information on the encryption keys (that is, the terminal 1050may be connected to a plurality of base stations at the same time).

For example, let it be assumed that there are three base stations 470.Herein, let the three base stations 470 be respectively referred to as abase station #A, a base station #B, and a base station #C. Furthermore,let it be assumed that the SSID of the base station #A is “abcdef”, theSSID of the base station #B is “ghijk”, and the SSID of the base station#C is “pqrstu”. Let it be further assumed that an encryption key forconnecting to the base station #A is “123”, an encryption key forconnecting to the base station #B is “456”, and an encryption key forconnecting to the base station #C is “789”.

In this case, the symbol 600-1 related to the SSID described in themodulated signal transmitted from the third device 1400A in the frameconfiguration shown in FIG. 18 includes information indicating the SSIDof the base station #A is “abcdef”, SSID of the base station #B is“ghijk” and the SSID of the base station #C is “pqrstu”. The symbol 1101related to the encryption key in the frame configuration shown in FIG.19 in the modulated signal transmitted by the fourth device 1400Bincludes information indicating that an encryption key for connecting tothe base station #A is “123”, an encryption key for connecting to thebase station #B is “456”, and an encryption key for connecting to thebase station #C is “789”.

The terminal 1050 shown in FIG. 17 receives the symbol 600-1 related tothe SSID thereby obtaining information indicating that the SSID of thebase station #A is “abcdef”, the SSID of the base station #B is “ghijk”,and the SSID of the base station #C is “pqrstu”. The terminal 1050 alsoreceives the symbol 1101 related to the encryption key thereby obtaininginformation indicating that the encryption key for connecting to thebase station #A is “123”, the encryption key for connecting to the basestation #B is “456” and the encryption key for connecting to the basestation #C is “789”. The terminal 1050 selects a base station to bewirelessly connected (for example, via a radio wave) based on thesepieces of information, and connects to the selected base stations.

By performing setting of the base station 470 to be accessed by theterminal 1050 using a light source such as an LED according to thepresent embodiment, it becomes unnecessary for the modulated signal forwireless communication transmitted by the terminal 1050 to have aspecial setting mode for a procedure to establish a wirelesscommunication connection between the terminal 1050 and the base station470. It also becomes unnecessary to provide, in the modulated signaltransmitted by the terminal 1050, a special setting mode for a procedureto make a wireless communication connection between the terminal 1050and the base station 470. Thus, according to the present embodiment, itis possible to improve the data transmission efficiency of wirelesscommunication.

As described above, the encryption key may be an encryption key for theSSID for the wireless LAN, or may be an encryption key for limiting theconnection mode, the service mode, the connection range of the network,and/or the like. That is, an encryption key may be introduced forimposing some restriction.

Embodiment 6

FIG. 22 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 6.

The communication system in FIG. 22 includes, for example, a basestation 2000 and a terminal 1050. The base station 2000 includes atransmission apparatus 2001 and a wireless apparatus 2002. In FIG. 22,elements that operate in similar manners to those shown in FIG. 6 orFIG. 13 are denoted by similar reference numerals. Note that it isassumed that communication between the wireless apparatus 2002 and thewireless apparatus 453 shown in FIG. 22 is performed using, for example,radio waves.

The transmission apparatus 2001 of the base station (or the AP) 2000shown in FIG. 22 includes, for example, a visible light source such asan LED, lighting, a light source, and a light (hereinafter, referred toas a light source 104). First, the operation of the transmissionapparatus 2001 (that is, “a part related to a visible light source suchas an LED, lighting, a light source, and light”) will be described.

In the transmission apparatus 2001, a transmitter 102 gets, as inputsthereto, information 1001-1 related to an SSID, information 1001-2related to an encryption key, and data 1002, and generates a (light)modulated signal 103 based on these input signals and outputs a resultas a modulated signal 103. The modulated signal 103 is transmitted, forexample, from a light source 104.

Next, information 1001-1 related to the SSID and information 1001-2related to the encryption key are described below.

First, the information 1001-1 related to the SSID is described.

The information 1001-1 related to the SSID is information indicating theSSID of the wireless apparatus 2002 using a radio wave in the basestation 2000 in FIG. 22. That is, the transmission apparatus 2001 canprovide, to the terminal 1050, access to the wireless apparatus 2002,which is a secure access destination via a radio wave. Thus, theterminal 1050 shown in FIG. 22 can securely obtain information from thewireless apparatus 2002.

On the other hand, the transmission apparatus 2001 can limit terminalsallowed to access the wireless apparatus 2002 to those terminals thatare located within a space in which it is possible to receive a lightsignal transmitted (emitted) by the transmission apparatus 2001.

When the terminal 1050 receives a light signal transmitted in apredetermined scheme, the terminal 1050 may determine that the notifiedSSID is an SSID of a secure base station. The terminal 1050 may performa separate process of determining whether the notified SSID is secure ornot. For example, the transmission apparatus 2001 may transmit a lightsignal including a predetermined identifier, and the terminal 1050 maydetermine whether the notified SSID is an SSID of a secure base stationor not based on the received identifier.

Although only the base station 2000 is shown as a base station in FIG.22, there may be one or more other base stations (or APs) in addition tothe base station 2000. Also, in such a case, the terminal 1050 mayaccess the wireless apparatus 2002 of the base station 2000 using theSSID and the encryption key obtained from the transmission apparatus2001 to acquire information.

Next, the information 1001-2 related to the encryption key is described.

The information 1001-2 related to the encryption key is informationrelated to an encryption key required for the terminal 1050 tocommunicate with the wireless apparatus 2002. By acquiring theinformation 1001-2 related to the encryption key from the transmissionapparatus 2001, it becomes possible for the terminal 1050 to performencrypted communication with the wireless apparatus 2002.

The information 1001-1 related to the SSID and the information 1001-2related to the encryption key have been described above.

The terminal 1050 in FIG. 22 receives the modulated signal transmittedfrom the transmission apparatus 2001. In the terminal 1050 shown in FIG.22, elements similar in operation to those in the terminal 150 shown inFIG. 6 or the terminal 1050 shown in FIG. 13 are denoted by similarreference numerals.

The light receiver 151 of the terminal 1050 is, for example, an imagesensor such as a CMOS sensor or an organic CMOS sensor. The lightreceiver 151 receives light including the modulated signal transmittedfrom the transmission apparatus 2001, and outputs a reception signal152.

The receiver 153 receives, as an input thereto, the reception signal 152received by the light receiver 151, and performs processing such asdemodulation/error correction decoding on the modulated signal includedin the reception signal 152 and outputs a result as reception data 154.

The data analysis unit 155 receives, as an input thereto, the receptiondata 154, and outputs, based on the reception data, for example,information 1051 on the SSID of the wireless apparatus 2002 of the basestation 2000 which is to be a connection destination and information1052 on the encryption key for use in communicating with the wirelessapparatus 2002 of the base station 2000 which is to be the connectiondestination. Encryption schemes for use in a wireless LAN (Local AreaNetwork) include, for example, WEP (Wired Equivalent Privacy), WPA(Wi-Fi Protected Access), WPA2 (Wi-Fi Protected Access 2) (PSK(Pre-Shared Key) mode, EAP (Extended Authentication Protocol) mode).Note that the encryption schemes are not limited to the examplesdescribed above.

The display 157 receives, as inputs thereto, the information 1051 on theSSID and the information 1052 on the encryption key, and displays, forexample, an SSID of a communication counterpart to be accessed by thewireless apparatus 453 of the terminal 1050 and an encryption key (thisdisplaying is referred to as “first displaying” according to the presentembodiment).

For example, after the first displaying, the wireless apparatus 453receives, as inputs thereto, the SSID information 1051 and theencryption key information 1052, and establishes a connection with thewireless apparatus 2002 of the base station 2000 (for example, a radiowave is used in the connection). In this situation, if the wirelessapparatus 2002 of the base station 2000 also communicates with thewireless apparatus 453 of the terminal 1050, the wireless apparatus 2002transmits a modulated signal using, for example, a radio wave.

Thereafter, the wireless apparatus 453 receives, as inputs thereto, thedata 1053 and the control signal 1054, and modulates the data 1053according to the control indicated by the control signal 1054 andtransmits a result as the modulated signal using a radio wave.

Then, for example, the wireless apparatus 2002 of the base station 2000performs data transmission (471) to a network and data reception (472)from the network. Thereafter, for example, the wireless apparatus 2002of the base station 2000 transmits a modulated signal to the terminal1050 using a radio wave.

The wireless apparatus 453 in the terminal 1050 performs processing suchas demodulation, error correction decoding, and/or the like on themodulated signal received via the radio wave thereby acquiring receptiondata 1056. The display 157 performs displaying based on the receptiondata 1056.

The frame configuration of the modulated signal transmitted by wirelessapparatus 2002 of the base station 2000 according to the presentembodiment is the same as the frame configuration according toEmbodiment 4 described above with reference to FIG. 14. That is, in FIG.14, a symbol 600-1 related to the SSD is a symbol for transmitting theinformation 1001-1 related to the SSID shown in FIG. 22, an encryptionkey symbol 1101 is a symbol for transmitting the information 1001-2related to the encryption key shown in FIG. 22, and a data symbol 1102is a symbol for transmitting the data 1002 shown in FIG. 22.

As shown in FIG. 14, the wireless apparatus 2002 of the base station2000 transmits a preamble 201, a control information symbol 202, asymbol 600-1 related to an SSID, a symbol 1101 related to an encryptionkey, and a data symbol 1102. The wireless apparatus 2002 of the basestation 2000 may transmit a frame including a symbol other than thesymbols shown in FIG. 14. The frame configuration, including the orderof transmitting symbols, is not limited to the configuration shown inFIG. 14.

The frame configuration of the modulated signal transmitted by wirelessapparatus 453 of the terminal 1050 according to the present embodimentis the same as the frame configuration according to Embodiment 4described above with reference to FIG. 15. That is, as shown in FIG. 15,the wireless apparatus 453 included in the terminal 1050 in FIG. 22transmits, for example, a preamble 1201 and then transmits a controlinformation symbol 1202 and an information symbol 1203.

The preamble 1201 is a symbol for use by the wireless apparatus 2002 ofthe base station 2000 in, when receiving the modulated signaltransmitted from the wireless apparatus 453, performing, for example,signal detection, time synchronization, frame synchronization, afrequency synchronization, frequency offset estimation and/or the like.

The control information symbol 1202 is, for example, a symbol includingdata such as information related to an error correction coding schemeand modulation scheme used by the terminal 1050 in generating amodulated signal, information related to a frame configuration, andinformation related to a transmission scheme, and/or the like. Thewireless apparatus 2002 of the base station 2000 performs processingsuch as demodulation on the modulated signal or the like based on theinformation included in the control information symbol 1202.

The information symbol 1203 is a symbol for the wireless apparatus 453of the terminal 1050 to transmit data.

The wireless apparatus 453 of the terminal 1050 may transmit a frameincluding a symbol other than the symbols shown in FIG. 15. For example,the wireless apparatus 453 may transmit a frame including a pilot symbol(a reference symbol) in the middle of the information symbol 1203, orthe like. The frame configuration, including the order of transmittingsymbols, is not limited to the configuration shown in FIG. 15. In FIG.15, a plurality of symbols may exist in a direction along the frequencyaxis. That is, in FIG. 15, symbols may exist at a plurality offrequencies (a plurality of carriers).

The frame configuration of the modulated signal transmitted by wirelessapparatus 2002 according to the present embodiment is the same as theframe configuration according to Embodiment 3 described above withreference to FIG. 11. That is, as shown in FIG. 11, the wirelessapparatus 2002 transmits, for example, a preamble 701, and thentransmits a control information symbol 702 and an information symbol703.

The preamble 701 is a symbol for use by the wireless apparatus 453 ofthe terminal 1050 in, when receiving a modulated signal transmitted bythe wireless apparatus 2002, performing, for example, signal detection,time synchronization, frame synchronization, frequency synchronization,frequency offset estimation, and/or the like.

The control information symbol 702 is, for example, a symbol includingdata such as information related to an error correction coding schemeand a modulation scheme used in generating a modulated signal,information related to a frame configuration, information related to atransmission scheme, and/or the like. The wireless apparatus 453 of theterminal 1050 performs processing such as demodulation or the like onthe modulated signal based on the information represented by the controlinformation symbol 702.

The information symbol 703 is a symbol used by the wireless apparatus2002 to transmit data.

The wireless apparatus 2002 of the base station 2000 shown in FIG. 22may transmit a frame including a symbol other than the symbols shown inFIG. 11. For example, the wireless apparatus 2002 may transmit a frameincluding a pilot symbol (a reference symbol) in the middle of theinformation symbol 703, or the like. The frame configuration, includingthe order of transmitting symbols, is not limited to the configurationshown in FIG. 11. In FIG. 11, a plurality of symbols may exist in adirection along the frequency axis. That is, in FIG. 11, symbols mayexist at a plurality of frequencies (a plurality of carriers).

For example, in a method, the modulated signal in the frameconfiguration shown in FIG. 14 may be transmitted by the transmissionapparatus 2001, for example, repeatedly at regular intervals. This makesit possible for a plurality of terminals 1050 to perform the operationas described above.

FIG. 23 is a flow chart illustrating an example of processing performedby the “transmission apparatus 2001 of the base station 2000”, the“terminal 1050”, and the “wireless apparatus 2002 of the base station2000” illustrated in FIG. 22.

First, the transmission apparatus 2001 transmits a modulated signal inthe frame configuration shown in FIG. 14 (ST1301).

The terminal 1050 receives the modulated signal transmitted from thetransmission apparatus 2001, and acquires the SSID of the base station2000 (the wireless apparatus 2002) to be accessed by the terminal 1050(ST1302).

The terminal 1050 also acquires an encryption key used for communicationwith the base station 2000 (the wireless apparatus 2002) to be accessedby the terminal 1050 (ST1303).

The terminal 1050 then makes a radio-wave connection to the wirelessapparatus 2002 of the base station 2000 (ST1304). When the terminal 1050receives a response from the base station 2000, the connection betweenthe terminal 1050 and the wireless apparatus 2002 of the base station2000 is completed (ST1305).

The terminal 1050 then transmits information related to the connectiondestination to the wireless apparatus 2002 of the base station 2000using a radio wave (ST1306).

The wireless apparatus 2002 of the base station 2000 obtains informationto be transmitted to the terminal 1050 from a network (ST1307).

The wireless apparatus 2002 of the base station 2000 transmits theobtained information to the terminal 1050 using a radio wave. Theterminal 1050 obtains this information (ST1308). The terminal 1050 may,for example, obtain necessary information from the network via thewireless apparatus 2002 of the base station 2000 when necessary.

As described above, since the terminal 1050 is connected to the wirelessapparatus 2002 of the base station 2000 based on the information on theSSID and the information on the encryption key transmitted from thetransmission apparatus 2001 of the base station 2000, the terminal 1050can securely acquire information via the base station 2000 guaranteed tobe secure. This is because when the terminal 1050 obtains informationfrom a modulated signal of visible light, use of the visible lightallows the user to easily determine whether the information source issecure or not. In contrast, for example, in a case where an SSID isacquired from a modulated signal of a radio wave transmitted via awireless LAN, it is difficult for a user to determine a device fromwhich the radio wave is received. Thus, from the point of view ofensuring the security of information, visible light communication ismore suitable for acquiring an SSID than wireless LAN communication.

In the present embodiment described above, by way of example, thetransmission apparatus 2001 transmits the information on the encryptionkey. However, for example, when the wireless apparatus 2002 of the basestation 2000 does not perform communication encrypted using anencryption key, the transmission apparatus 2001 may transmit only theinformation on the SSID without transmitting the information on theencryption key. This can be achieved simply by deleting part related tothe encryption key from the configuration of the transmission apparatus2001.

As shown in FIG. 22, the wireless apparatus 2002 of the base station2000 may be configured such that the SSID and the encryption keyassociated with the wireless apparatus 2002 are allowed to be rewritten.For example, in FIG. 22, the wireless apparatus 2002 receives, as inputsthereto, information 1001-1 related to the SSID and information 1001-2related to the encryption key. The wireless apparatus 2002 of the basestation 2000 rewrites the SSID and the encryption key with the inputinformation 1001-1 related to the SSID and the information 1001-2related to the encryption key. This makes it possible to further enhancethe security in the communication between the terminal 1050 and thewireless apparatus 2002 of the base station 2000. In FIG. 22, thewireless apparatus 2002 of the base station 2000 has the function ofrewriting the SSID and the encryption. However, the wireless apparatus2002 may not have the function of rewriting one of or any of one of theSSID and the encryption key.

The configuration of the transmission apparatus is not limited to theconfiguration of the transmission apparatus 2001 shown in FIG. 22. Theconfiguration of the terminal is not limited to the configuration of theterminal 1050 shown in FIG. 22. The connection destination to which thewireless apparatus is connected and the configuration of the connectiondestination device are not limited to the connection destination towhich the wireless apparatus 2002 is connected and the configuration ofthe connection destination device shown in FIG. 22.

Furthermore, although in the example shown in FIG. 22, the base station2000 is the only base station existing there, there may be a pluralityof wireless apparatuses 2002 in (secure) base stations (or APs) 2000which can be accessed by the terminal 1050. The plurality of thewireless apparatuses 2002 of the base stations 2000 and the terminal1050 transmit and receive modulated signals using radio waves. In thiscase, the symbol related to the SSID transmitted by the transmissionapparatus 2001 shown in FIG. 22 may include information on the SSID ofeach of the plurality of wireless apparatuses 2002 of the base stations2000. The symbol related to the encryption key transmitted by thetransmission apparatus 2001 shown in FIG. 22 may include information onthe encryption key used to connect to each of the plurality of wirelessapparatuses 2002 of the base stations 2000. The terminal 1050 in FIG. 22may select a wireless apparatus 2002 of a base station 2000 to bewirelessly connected (for example, using a radio wave) based on theinformation on the SSIDs of the plurality of wireless apparatuses 2002of base stations 2000 and the information on the encryption keys (thatis, the terminal 1050 may be connected to a plurality of wirelessapparatuses of base stations).

For example, let it be assumed that there are three base stations 2000each having a wireless apparatus 2002. Let the three wirelessapparatuses 2002 of the base stations 2000 be respectively denoted as awireless apparatus #A, a wireless apparatus #B, and a wireless apparatus#C. Furthermore, let it be assumed that the SSID of the wirelessapparatus #A is “abcdef”, the SSID of the wireless apparatus #B is“ghijk”, and the SSID of the wireless apparatus #C is “pqrstu”. Let itbe further assumed that an encryption key for connecting to the wirelessapparatus #A is “123”, an encryption key for connecting to the wirelessapparatus #B “456”, and an encryption key for connecting to the wirelessapparatus #C is “789”.

In this case, the symbol 600-1 related to the SSID transmitted from thetransmission apparatus 2001 using the modulated signal having the frameconfiguration shown in FIG. 14 includes information indicating that theSSID of the wireless apparatus #A is “abcdef”, SSID of the wirelessapparatus #B is “ghijk” and the SSID of the wireless apparatus #C is“pqrstu”. The symbol 1101 related to the encryption key in the frameconfiguration of FIG. 14 includes information indicating that anencryption key for connecting to the wireless apparatus #A is “123”, anencryption key for connecting to the wireless apparatus #B is “456”, andan encryption key for connecting to the wireless apparatus #C is “789”.

The terminal 1050 in FIG. 22 receives the symbol 600-1 related to theSSID thereby obtaining information indicating that the SSID of thewireless apparatus #A is “abcdef”, the SSID of the wireless apparatus #Bis “ghijk”, and the SSID of the wireless apparatus #C is “pqrstu”. Theterminal 1050 also receives the symbol 1101 related to the SSID therebyobtaining information indicating that the encryption key for connectingto the wireless apparatus #A is “123”, the encryption key for connectingto the wireless apparatus #B is “456”, and the encryption key forconnecting to the wireless apparatus #C is “789”. The terminal 1050selects a base station to be wirelessly connected (for example, via aradio wave) based on these pieces of information, and connects to theselected base stations.

By performing setting of the wireless apparatus 2002 of the base station2000 to be accessed by the terminal 1050 using a light source such as anLED according to the present embodiment, it becomes unnecessary for themodulated signal for wireless communication transmitted by the terminal1050 to have a special setting mode for a procedure to establish awireless communication connection between the terminal 1050 and the basestation 2000. It also becomes unnecessary to provide, in the modulatedsignal transmitted by the terminal 1050, a special setting mode for aprocedure to make a wireless communication connection between theterminal 1050 and the base station 2000. Thus, according to the presentembodiment, it is possible to improve the data transmission efficiencyof wireless communication.

As described above, the encryption key may be an encryption key for theSSID for the wireless LAN, or may be an encryption key for limiting theconnection mode, the service mode, the connection range of the network,and/or the like. That is, an encryption key may be introduced forimposing some restriction.

Embodiment 7

FIG. 24 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 7.

The communication system in FIG. 24 includes a device 1000, a terminal1050, a base station (or an AP) 470-1 (a base station #1), a basestation (or an AP) 470-2 (a base station #2), and a base station (or anAP) 470-3 (a base station #3), that communicate with the terminal 1050.In FIG. 24, elements that operate in similar manners to those shown inFIG. 6, FIG. 9, or FIG. 13 are denoted by similar reference numerals.

The device 1000 includes, for example, a visible light source such as anLED, lighting, a light source, and a light (hereinafter, referred to asa light source 104). Hereinafter, the device 1000 may also be referredto as a “fifth device” according to the present embodiment. Note that itis assumed that communication between the wireless apparatus 453 and theterminal 470-1 (the base station #1), between the wireless apparatus 453and the base station 470-2 (the base station #2), and between thewireless apparatus 453 and the base station 470-3 (the base station #3)shown in FIG. 24 is performed using, for example, radio waves.

In the fifth device 1000 shown in FIG. 24, a transmitter 101 gets, asinputs thereto, information 1001-1 related to an SSID, information1001-2 related to an encryption key, and data 1002, and the fifth device1000 generates a (light) modulated signal 103 based on these inputsignals and outputs the resultant modulated signal 103. The modulatedsignal 103 is transmitted, for example, from a light source 104.

Next, information 1001-1 related to the SSID and information 1001-2related to the encryption key are described below.

First, the information 1001-1 related to the SSID is described.

The information 1001-1 related to the SSID includes, for example,information indicating the SSID of the base station 470-1 (the basestation #1), information indicating the SSID of the base station 470-2(the base station #2), information indicating the SSID of the station470-3 (the base station #3) shown in FIG. 24. By way of example, thebase stations 470-1, 470-2, and 470-3 transmit modulated signals viaradio waves and receive modulated signals via radio waves. That is, thefifth device 1000 can provide, to the terminal 1050, access to the basestations 470-1, 470-2 and 470-3 which are secure access destinations.This allows the terminal 1050 in FIG. 24 to obtain information securelyfrom the base stations 470-1, 470-2, and 470-3.

On the other hand, the fifth device 1000 can limit terminals allowed toaccess the base stations 470-1, 470-2, and 470-3 to those terminals thatare located within a space in which it is possible to receive a lightsignal transmitted (emitted) by the fifth device 1000.

When the terminal 1050 receives a light signal transmitted in apredetermined scheme, the terminal 1050 may determine that the notifiedSSID is an SSID of a secure base station. The terminal 1050 may performa separate process of determining whether the notified SSID is secure ornot. For example, the fifth device 1000 may transmit a light signalincluding a predetermined identifier, and the terminal 1050 maydetermine whether the notified SSID is an SSID of a secure base stationor not based on the received identifier.

FIG. 24 illustrates the base stations 470-1, 470-2, and 470-3, but, forexample, a base station (or an AP) other than the base stations 470-1,470-2, and 470-3 may exist.

Next, the information 1001-2 related to the encryption key is described.

The encryption key information 1001-2 is information related to anencryption key required for the terminal 1050 to communicate with thebase stations 470-1, 470-2, and 470-3. When the terminal 1050 obtainsthe information 1001-2 related to the encryption key from the fifthdevice 1000, it becomes possible to perform encrypted communicationbetween the terminal 1050 and the base station 470-1, between theterminal 1050 and the base station 470-2, and between the terminal 1050and the base station 470-3.

The information 1001-1 related to the SSID and the information 1001-2related to the encryption key have been described above.

The terminal 1050 in FIG. 24 receives a modulated signal transmitted bythe fifth device 1000. In the terminal 1050 shown in FIG. 24, elementssimilar in operation to those in the terminal 150 shown in FIG. 6 or theterminal 450 shown in FIG. 9 are denoted by similar reference numerals.

The light receiver 151 of the terminal 1050 is, for example, an imagesensor such as a CMOS sensor or an organic CMOS sensor. The lightreceiver 151 receives light including the modulated signal transmittedfrom the fifth device 1000, and outputs a reception signal 152.

The receiver 153 receives, as an input thereto, the reception signal 152received by the light receiver 151, and performs processing such asdemodulation/error correction decoding on the modulated signal includedin the reception signal 152 and outputs a result as reception data 154.

The data analysis unit 155 receives, as an input thereto, the receptiondata 154, and outputs, based on the reception data 154, for example,information 1051 on the SSIDs of the base stations 470-1, 470-2, and470-3 to be connected and outputs information 1052 on encryption keysfor communicating with the base stations 470-1, 470-2, and 470-3 to beconnected. Encryption schemes for use in a wireless LAN (Local AreaNetwork) include, for example, WEP (Wired Equivalent Privacy), WPA(Wi-Fi Protected Access), WPA2 (Wi-Fi Protected Access 2) (PSK(Pre-Shared Key) mode, EAP (Extended Authentication Protocol) mode).Note that the encryption schemes are not limited to the examplesdescribed above.

The display 157 receives, as inputs thereto, the information 1051 on theSSID and the information 1052 on the encryption key, and displays, forexample, an SSID of a communication counterpart to be accessed by thewireless apparatus 453 of the terminal 1050 and an encryption key (thisdisplaying is referred to as “first displaying” according to the presentembodiment).

For example, after the first displaying, the wireless apparatus 453receives, as inputs thereto, the information 1051 on the SSIDs and theinformation 1052 on the encryption keys, and establishes a connectionwith one of the base stations 470-1, 470-2, and 470-3 (for example, aradio wave is used in the connection). In this situation, if theconnected base station 470 also communicates with the wireless apparatus453 of the terminal 1050, the base station 470 transmits a modulatedsignal using, for example, a radio wave.

Thereafter, the wireless apparatus 453 receives, as inputs thereto, thedata 1053 and the control signal 1054, and modulates the data 1053according to the control indicated by the control signal 1054 andtransmits a result as the modulated signal using a radio wave.

Then, for example, the connected base station 470 performs datatransmission (one of 471-1, 471-2, and 471-3) to a network and datareception (one of 472-1, 472-2, and 472-3) from the network. Thereafter,for example, the connected base station 470 transmits a modulated signalto the terminal 1050 using a radio wave.

The wireless apparatus 453 in the terminal 1050 performs processing suchas demodulation, error correction decoding, and/or the like on themodulated signal received via the radio wave thereby acquiring receptiondata 1056. The display 157 performs displaying based on the receptiondata 1056.

In the case shown in FIG. 24, there are three types of frameconfigurations for use in the modulated signal transmitted by the fifthdevice 1000 configurations. FIG. 25 illustrates a frame 2300-1 (a frame#1) which is one of three types of frame configurations. FIG. 26illustrates a frame 2300-2 (a frame configuration #2) which is one ofthree types of frame configurations. FIG. 27 illustrates a frame 2300-3(a frame configuration #3) which is one of three types of frameconfigurations.

FIG. 25 illustrates an example of a configuration of the frame 2300-1(the frame #1) of the modulated signal transmitted by the fifth device1000. In FIG. 25, a horizontal axis represents time. In FIG. 25, symbolssimilar to those shown in FIG. 2 or FIG. 14 are denoted by the samereference numerals, and a description thereof is omitted. The frame2300-1 (the frame #1) shown in FIG. 25 is a frame for transmittinginformation on the SSID of the base station 470-1 (the base station #1)shown in FIG. 24 and information on the encryption key of the basestation 470-1 (the base station #1) (the encryption key for accessingthe base station 470-1.

A symbol 2301-1 related to an SSID is a symbol for transmitting theinformation 1001-1 related to the SSID shown in FIG. 24. A symbol 2301-1related to an SSID is a symbol used by the fifth device 1000 in FIG. 24to transmit the SSID of the base station 470-1 (the base station #1).

A symbol 2302-1 related to an encryption key is a symbol fortransmitting the information 1001-2 related to the encryption key shownin FIG. 24. The symbol 2302-1 related to the encryption key is also asymbol used by the fifth device 1000 in FIG. 24 to transmit theencryption key of the base station 470-1 (the base station #1) (theencryption key for accessing the base station 470-1).

The fifth device 1000 transmits a preamble 201, a control informationsymbol 202, a symbol 2301-1 relating to an SSID, a symbol 2302-1relating to an encryption key, and a data symbol 1102. The frame 2300-1(the frame #1) transmitted by the fifth device 1000 may include a symbolother than the symbols described in FIG. 25. The configuration of theframe 2300-1 (the frame #1), including the order of transmittingsymbols, is not limited to the configuration shown in FIG. 25.

FIG. 26 illustrates an example of a configuration of the frame 2300-2(the frame #2) of the modulated signal transmitted by the fifth device1000. In FIG. 26, a horizontal axis represents time. In FIG. 26, symbolssimilar to those shown in FIG. 2 or FIG. 14 are denoted by similarreference numerals, and a description thereof is omitted. The frame2300-2 (the frame #2) shown in FIG. 26 is a frame for transmittinginformation on the SSID of the base station 470-2 (the base station #2)shown in FIG. 24 and information on the encryption key of the basestation 470-2 (the base station #2) (the encryption key for accessingthe base station 470-2.

A symbol 2301-2 related to an SSID is a symbol for transmitting theinformation 1001-1 related to the SSID shown in FIG. 24. A symbol 2301-2related to the SSID is a symbol used by the fifth device 1000 in FIG. 24to transmit the SSID of the base station 470-2 (the base station #2).

A symbol 2302-2 related to an encryption key is a symbol fortransmitting the information 1001-2 related to the encryption key shownin FIG. 24. The symbol 2302-2 related to the encryption key is also asymbol used by the fifth device 1000 in FIG. 24 to transmit theencryption key of the base station 470-2 (the base station #2) (theencryption key for accessing the base station 470-2).

The fifth device 1000 transmits a preamble 201, a control informationsymbol 202, a symbol 2301-2 relating to an SSID, a symbol 2302-2relating to an encryption key, and a data symbol 1102. The frame 2300-2(the frame #2) transmitted by the fifth device 1000 may include a symbolother than the symbols described in FIG. 26. The configuration of theframe 2300-2 (the frame #2), including the order of transmittingsymbols, is not limited to the configuration shown in FIG. 26.

FIG. 27 illustrates an example of a configuration of the frame 2300-3(the frame #3) of the modulated signal transmitted by the fifth device1000. In FIG. 27, a horizontal axis represents time. In FIG. 27, symbolssimilar to those shown in FIG. 2 or FIG. 14 are denoted by similarreference numerals, and a description thereof is omitted. The frame2300-3 (the frame #3) shown in FIG. 27 is a frame for transmittinginformation on the SSID of the base station 470-3 (the base station #3)shown in FIG. 24 and information on the encryption key of the basestation 470-3 (the base station #3) (the encryption key for accessingthe base station 470-3).

A symbol 2301-3 related to an SSID is a symbol for transmitting theinformation 1001-1 related to the SSID shown in FIG. 24. A symbol 2301-3related to the SSID is a symbol used by the fifth device 1000 in FIG. 24to transmit the SSID of the base station 470-3 (the base station #3).

A symbol 2302-3 related to an encryption key is a symbol fortransmitting the information 1001-2 related to the encryption key shownin FIG. 24. The symbol 2302-3 related to the encryption key is also asymbol used by the fifth device 1000 to transmit the encryption key ofthe base station 470-3 (the base station #3) (the encryption key foraccessing the base station 470-3).

The fifth device 1000 transmits a preamble 201, a control informationsymbol 202, a symbol 2301-3 relating to an SSID, a symbol 2302-3relating to an encryption key, and a data symbol 1102. The frame 2300-3(the frame #3) transmitted by the fifth device 1000 may include a symbolother than the symbols described in FIG. 27. The configuration of theframe 2300-3 (the frame #3), including the order of transmittingsymbols, is not limited to the configuration shown in FIG. 27.

FIG. 28 illustrates an example of a manner in which the fifth device1000 transmits “the frame 2300-1 (the frame #1 in FIG. 25), “the frame2300-2 (the frame #2 in FIG. 26)”, and “the frame 2300-3 in FIG. 27 (theframe #3). In FIG. 28, a horizontal axis represents time.

In “transmission of frame #1 group” 2601-1 and 2601-2 in FIG. 28, one ormore frames 2300-1 (frames #1) shown in FIG. 25 are transmitted. In“transmission of frame #2 group” 2602-1 and 2602-2, one or more frames2300-2 (frames #2) shown in FIG. 26 are transmitted. In “transmission offrame #3 group” 2603-1 and 2603-2, one or more frames 2300-3 (frames #3)shown in FIG. 27 are transmitted.

The transmissions are described in further detail below.

First, a description is given as to the “transmission of frame #1 group”2601-1 and 2601-2 in which one or more frames 2300-1 (frame #1) shown inFIG. 25 are transmitted.

For example, in the case where a CMOS sensor or an organic CMOS sensoris used as an image sensor in the light receiver 151, there is apossibility that a reception signal is processed in units of frames of amoving image or a still image. For example, when “4K 30p” is describedfor a moving image, this means that the number of pixels in each frameis 3840×2160 and the number of frames per second is 30.

Therefore, when a modulated signal transmitted by the fifth device 1000is configured such that “a frame 2300-1 (a frame #1) shown in FIG. 25”,“a frame 2300-2 (a frame #2) shown in FIG. 26”, and “a frame 2300-3 (aframe #3) shown in FIG. 27” exist in one frame, it is difficult for theterminal 1050 in FIG. 24 to select a base station 470 to be accessedfrom the base stations 470-1, 470-2, and 470-3.

In view of the above, in the present embodiment, a frame configurationsuch as that shown in FIG. 28 is proposed.

<Method 1-1>

In Method 1-1, each of the “transmission of frame #1 group” 2601-1 and2601-2 includes a plurality of frames 2300-1 (frames #1) shown in FIG.25 such that each of the “transmission of frame #1 group” 2601-1 and2601-2 occupies a time interval longer than the frame length in themoving image or the still image.

By employing this method, it is ensured that the modulated signalreceived by the terminal 1050 from the fifth device 1000 is preventedfrom having a configuration in which a “frame 2300-1 (a frame #1) shownin FIG. 25”, a “frame 2300-2 (a frame #2) shown in FIG. 26”, and a“frame 2300-3 (a frame #3) shown in FIG. 27” are included in one frameof a moving image or a still image, that is, it is ensured that thereceived modulated signal does not include different SSIDs or differentencryption keys. Thus, the terminal 1050 in FIG. 24 can easily select abase station 470 to be accessed from a plurality of base stations 470-1,470-2, and 470-3.

<Method 2-1>

In Method 2-1, a time interval occupied by the frame 2300-1 (the frame#1) in FIG. 25 is set to be longer than the frame length of a movingimage or a still image.

For example, the symbol 2301-1 related to the SSID in FIG. 25 mayinclude a plurality of pieces of “information on the SSID of the basestation #1” (that is, “the information on the SSID of the base station#1” may be repeatedly included), and the symbol 2302-1 related to theencryption key may include a plurality of pieces of “information on theencryption key of the base station #1 (information on the encryption keyfor connecting to the base station #1)” (that is, “the information onthe encryption key of the base station #1 (the information on theencryption key for connection to the base Station #1) may be repeatedlyincluded).

By employing this method, it is ensured that the modulated signalreceived by the terminal 1050 from the fifth device 1000 is preventedfrom having a configuration in which a “frame 2300-1 (a frame #1) shownin FIG. 25”, a “frame 2300-2 (a frame #2) shown in FIG. 26”, and a“frame 2300-3 (a frame #3) shown in FIG. 27” are included in one frameof a moving image or a still image, that is, it is ensured that thereceived modulated signal does not include different SSIDs or differentencryption keys. Thus, the terminal 1050 can easily select a baseStation 470 to be accessed from a plurality of base stations 470-1,470-2, and 470-3.

Similarly, it may be desirable to configure the “transmission of frame#2 group” 2602-1 and 2602-2 as described below.

<Method 1-2>

In Method 1-2, each of the “transmission of frame #2 group” 2602-1 and2602-2 includes a plurality of frames 2300-2 (frames #2) shown in FIG.26 such that a time interval occupied by the “transmission of frame #2group” is longer than the frame length of a moving image or a stillimage.

<Method 2-2>

In Method 2-2, a time interval occupied by the frame 2300-2 (the frame#2) in FIG. 26 is set to be longer than the frame length of a movingimage or a still image.

For example, the symbol 2301-2 related to the SSID in FIG. 26 mayinclude a plurality of pieces of “information on the SSID of the basestation #2” (that is, “the information on the SSID of the base station#2” may be repeatedly included), and the symbol 2302-2 related to theencryption key may include a plurality of pieces of “information on theencryption key of the base station #2 (information on the encryption keyfor connecting to the base station #2)” (that is, “the information onthe encryption key of the base station #2 (the information on theencryption key for connection to the base station #2) may be repeatedlyincluded).

Similarly, it may be desirable to configure the “transmission of frame#3 group” 2603-1 and 2603-2 as described below.

<Method 1-3>

In Method 1-3, each of the “transmission of frame #3 group” 2603-1 and2603-2 includes a plurality of frames 2300-3 (frames #3) shown in FIG.27 such that a time interval occupied by the “transmission of frame #3group” is longer than the frame length of a moving image or a stillimage.

<Method 2-3>

In Method 2-3, a time interval occupied by the frame 2300-3 (the frame#3) in FIG. 27 is set to be longer than the frame length of a movingimage or a still image.

For example, the symbol 2301-3 related to the SSID in FIG. 27 mayinclude a plurality of pieces of “information on the SSID of the basestation #3” (that is, “the information on the SSID of the base station#3” may be repeatedly included), and the symbol 2302-3 related to theencryption key may include a plurality of pieces of “information on theencryption key of the base station #3 (information on the encryption keyfor connecting to the base station #3)” (that is, “the information onthe encryption key of the base station #3 (the information on theencryption key for connection to the base station #3) may be repeatedlyincluded).

Next, effects obtained when the fifth device 1000 transmits a frame asshown in FIGS. 25 to 28 will be described.

A discussion is given below, by way for example, with reference to anarea 2700 in FIG. 29. In FIG. 29, fifth devices 1000 are located atrespective locations denoted by circles 2701-1, 2701-2, 2701-3, 2701-4,2701-5, 2701-6, 2701-7, 2701-8, 2701-8, 2701-9, and 2701-10. A basestation 470-1 (a base station #1) is located at a location denoted by adouble circle 2702-1. A base station 470-2 (a base station #2) islocated at a location denoted by a double circle 2702-2. A base station470-3 (a base station #3) is located at a location denoted by a doublecircle 2702-3.

It is assumed by way of example that there are 99 terminals(hereinafter, simply referred to as terminals 1050) having a similarconfiguration to the configuration of the terminal 1050 in the area2703.

In this situation, for example, fifth devices 1000 located at locationsdenoted by circles 2701-5 and 2701-10 both transmit information on theSSID of the base station 470-3 (the base station #3), and also transmitinformation on the encryption key for accessing the station 470-3 (thebase station #3). This is because the base station 470-3 (the basestation #3) is a base station located closest to the locations denotedby circles 2701-5 and 2701-10.

In this case, all 99 terminals 1050 may access the base station 470-3(the base station #3). This may cause too much accessing to occur, whichmay lead to a high possibility that there is a terminal 1050 having adifficulty in accessing the base station 470-3 (the base station #3).

To handle such a situation, accessing may be controlled such thataccessing by 99 terminals 1050 is as evenly distributed as possibleamong the base station 470-1 (the base station #1) (at the locationdenoted by the circle 2702-1), the base station 470-2 (the base station#2) (at the location denoted by the circle 2702-2), and the base station470-3 (the base station #3) (at the location denoted by the circle2702-3) thereby reducing the number of terminals 1050 having adifficulty in accessing a base station 470.

The timing of accessing the fifth device 1000 by the 99 terminals 1050is generally different among the terminals 1050. Therefore, when thefifth device 1000 transmits a frame according to the present embodimentas shown in FIGS. 25 to 28, each of the 99 terminals 1050 obtains anSSID and an encryption key of one of the base stations 470-1, 470-2, and470-3 depending on the timing of accessing the fifth device 1000. As aresult, controlling is performed such that “accessing by the 99terminals 1050 to the base stations 470-1, 470-2, and 470-3 isdistributed as evenly as possible among the base stations 470-1, 470-2,and 470-3”. Thus, it is possible to reduce the number of terminals 1050having a difficulty in accessing the base station 470.

Note that in the example shown in FIG. 28, a transmission manner isshown for a case where the fifth device 1000 transmits the “frame 2300-1(the frame #1) in FIG. 25”, the “frame 2300-2 (the frame #2) in FIG.26”, and the “frame 2300-3 (the frame #3) in FIG. 27”. However, when thefifth device 100 transmits the “frame 2300-1 (the frame #1) in FIG.25),” the “frame 2300-2 (the frame #2) in FIG. 26),” and the “frame2300-3 (the frame #3) in FIG. 27),” the transmission manner is notlimited to the example described above.

For example, FIG. 28 shows a transmission manner in which the fifthdevice 1000 repeatedly performs the “transmission of frame #1 group”,the “transmission of frame #2 group”, and the “transmission of frame #3group” in this order. However, the “transmission of frame #1 group”, the“transmission of frame #2 group”, and the “transmission of frame #3group” do not need to be performed in the order shown in FIG. 28.Alternatively, for example, the fifth device 1000 may perform the“transmission of frame #1 group”, the “transmission of frame #2 group”,and the “transmission of frame #3 group” randomly in time, or mayperform the “transmission of frame #1 group”, the “transmission of frame#2 group”, and the “transmission of frame #3 group” in a regular orderdifferent from the order shown in FIG. 28. What is required is toperform at least the “transmission of frame #1 group”, the “transmissionof frame #2 group”, and the “transmission of frame #3 group” by thefifth device 1000.

In the example shown in FIG. 28, the “transmission of frame #1 group”,the “transmission of frame #2 group”, and the “transmission of frame #3group” are continuously performed by the fifth device 1000. However, thetransmissions do not necessarily need to be performed continuously. Forexample, in FIG. 28, there may be a time interval between thetransmission of the frame-#1 group 2601-1 and the transmission of theframe-#2 group 2602-2.

Furthermore, in the example shown in FIG. 28, only the “transmission offrame #1 group”, the “transmission of frame #2 group”, and the“transmission of frame #3 group” are performed. However, other symbolsor other frames may also be transmitted. Furthermore, in FIG. 28 andFIG. 24, although the number of base stations 470 is three, the numberof base stations 470 is not limited to three. Also in a case where thenumber of base stations 470 is two or more, the operation can beperformed in a similar manner to the case where the number of basestations 470 is three. For example, in a case where there are N basestations 470 (N is an integer equal to or greater than 2), when thefifth device 1000 performs transmission in a manner as shown in FIG. 28,“transmission of frame #k group” is performed where k is an integer in arange from 1 to N (inclusive). The “frame #k group transmission”includes transmission of a symbol related to an SSID (information on anSSID of the base station #k), and a symbol related to an encryption key(information on an encryption key for accessing to the base station #k.

The frame configuration of a modulated signal transmitted by thewireless apparatus 453 included in the terminal 1050 in FIG. 24 is thesame as the frame configuration in FIG. 15 according to Embodiment 4described above. That is, as shown in FIG. 15, the wireless apparatus453 in the terminal 1050 shown in FIG. 24 transmits, for example, apreamble 1201, and then transmits a control information symbol 1202 andan information symbol 1203.

The preamble 1201 is a symbol used by the base stations 470-1, 470-2,and 470-3 in, when receiving the modulated signal transmitted by thewireless apparatus 453 of the terminal 1050, performing, for example,signal detection, time synchronization, frame synchronization, frequencysynchronization, frequency offset estimation, and/or the like.

The control information symbol 1202 is, for example, a symbol includingdata such as information related to an error correction coding schemeand a modulation scheme used in generating a modulated signal,information related to a frame configuration, and information related toa transmission scheme, and/or the like. The base stations 470-1, 470-2,and 470-3 perform processing such as demodulation on the modulatedsignal or the like based on the information included in the controlinformation symbol 1202.

The information symbol 1203 is a symbol for the wireless apparatus 453of the terminal 1050 to transmit data.

Note that the wireless apparatus 453 of the terminal 1050 in FIG. 24 maytransmit a frame including a symbol other than the symbols described inFIG. 15 (for example, the wireless apparatus 453 may transmit a frameincluding a pilot symbol (a reference symbol) in the middle of theinformation symbol 1203). The frame configuration, including the orderof transmitting symbols, is not limited to the configuration shown inFIG. 15. In FIG. 15, a plurality of symbols may exist in a directionalong the frequency axis. That is, symbols may exist at a plurality offrequencies (a plurality of carriers).

Frame configurations of modulated signals transmitted by the basestations 470-1, 470-2, and 470-3 in FIG. 24 are the same as the frameconfiguration in FIG. 11 according to Embodiment 3 described above. Thatis, as shown in FIG. 11, the base stations 470-1, 470-2, and 470-3transmit, for example, a preamble 701, and then transmits a controlinformation symbol 702 and an information symbol 703.

The preamble 701 is a symbol for use by the wireless apparatus 453 ofthe terminal 1050 in, when receiving a modulated signal transmitted bythe base stations 470-1, 470-2, or 470-3, performing, for example,signal detection, time synchronization, frame synchronization, frequencysynchronization, frequency offset estimation, and/or the like.

The control information symbol 702 is, for example, a symbol includingdata such as information related to an error correction coding schemeand a modulation scheme used in generating a modulated signal,information related to a frame configuration, information related to atransmission scheme, and/or the like. The wireless apparatus 453 of theterminal 1050 performs processing such as demodulation or the like onthe modulated signal based on the information represented by the controlinformation symbol 702.

The information symbol 703 is a symbol used by the base stations 470-1,470-2, and 470-3 to transmit data.

The base stations 470-1, 470-2, and 470-3 may transmit a frame includinga symbol other than the symbols shown in FIG. 11. For example, the basestations 470-1, 470-2, and 470-3 may transmit a frame or the likeincluding a pilot symbol (a reference symbol) in the middle of theinformation symbol 703. The frame configuration, including the order oftransmitting symbols, is not limited to the configuration shown in FIG.11. In FIG. 11, a plurality of symbols may exist in a direction alongthe frequency axis. That is, in FIG. 11, symbols may exist at aplurality of frequencies (a plurality of carriers).

FIG. 30 is a flow chart illustrating an example of processing performedby the “fifth device 1000”, the “terminal 1050”, and the “base station#X” where X is 1 or 2 or 3.

First, the fifth device 1000 transmits a modulated signal in the frameconfiguration shown in FIG. 28 (ST2801).

The terminal 1050 receives the modulated signal transmitted by the fifthdevice 1000, and selects a base station that the terminal 1050 is toaccess, from the base station 470-1 (the base station #1), the basestation 470-2 (the base station #2), and the base station 470-3 (thebase station #3) shown in FIG. 24 (ST2802).

A further description regarding this is given below. In order to accessone of the base stations 470, the terminal 1050 receives a modulatedsignal transmitted by the fifth device 1000. As a result, for example,the terminal 1050 obtains one of the “transmission of frame #1 group”,the “transmission of frame #2 group”, and the “transmission of frame #3group” in FIG. 28 in a certain frame of a moving image or a still image.Based on the obtained information (for example, SSIDs) on the basestations, the terminal 1050 selects one the base station 470-1 (the basestation #1), the base station 470-2 (the base station #2), and the basestation 470-3 (the base station #3) as the base station 470 that theterminal 1050 is to access.

Next, the terminal 1050 receives the modulated signal transmitted by thefifth device 1000, and acquires an SSID of the base station #X to beaccessed by the terminal 1050 (ST2803).

The terminal 1050 also acquires an encryption key used for communicatingwith the base station #X to be accessed by the terminal 1050 (ST2804).

The terminal 1050 then makes connection to the base station #X using aradio wave (ST2805). When the terminal 1050 receives a response from thebase station #X, the connection between the terminal 1050 and the basestation #X is completed (ST2806).

The terminal 1050 then transmits information on the connectiondestination to the base station #X using a radio wave (ST2807).

The base station #X obtains, from a network, information to betransmitted to the terminal 1050 (ST2808).

The base station #X transmits the obtained information to the terminal1050 using a radio wave. Thus, the terminal 1050 obtains the information(ST2809). The terminal 1050 acquires necessary information from thenetwork via the base station #X, for example, when necessary.

As described above, the terminal 1050 connects to the base station 470based on the information on the SSID and the information on theencryption key transmitted from the fifth device 1000, and thus theterminal 1050 can securely acquire information via the base station 470whose security is guaranteed. This is because information is obtainedfrom a modulated signal of visible light, use of the visible lightallows the user to easily determine whether the information source issecure or not. In contrast, for example, in a case where an SSID isacquired from a modulated signal of a radio wave transmitted via awireless LAN, it is difficult for a user to determine a device fromwhich the radio wave is received. Thus, from the point of view ofensuring the security of information, visible light communication ismore suitable for acquiring an SSID than wireless LAN communication.

In the present embodiment described above, by way of example, the fifthdevice 1000 transmits the information on the encryption key. However,for example, when the base station 470 does not perform communicationencrypted using an encryption key, the fifth device 1000 may transmitonly the information on the SSID without transmitting the information onthe encryption key. In this case, the operation may be performed in asimilar manner as described above except that part of the operationrelated to the encryption key described above is not performed.

Note that the configuration of the fifth device is not limited to thespecific configuration of the fifth device 1000 shown in FIG. 24. Theconfiguration of the terminal is not limited to the configuration of theterminal 1050 shown in FIG. 24. The connection destination devices towhich the base stations #1, #2, and #3 are connected and theconfigurations of the connection destination devices are not limited tothe connection destination devices to which the base stations 470-1,470-2, and 470-3 are connected and the configurations of the connectiondestination devices shown in FIG. 24.

Furthermore, according to the present embodiment, it is possible toreduce the number of terminals 1050 having a difficulty in accessing thebase station 470 even in a case where a plurality of terminals 1050exist in a particular area.

In FIG. 29, frame configurations of modulated signals transmitted by thefifth devices 1000 located at location denoted by circles 2701-1,2701-2, 2701-3, 2701-4, 2701-5, 2701-6, 2701-7, 2701-8, 2701-8, 2701-9,and 2701-10 may all be similar to the frame configuration shown in FIG.28, or modulated signals transmitted by the fifth devices 1000 may havedifferent frame configurations. There may be a plurality of fifthdevices 1000 that transmit modulated signals using the same frameconfiguration.

Although the configuration shown in FIG. 5 has been described as anexample of a configuration used in a communication system that performsvisible light communication, the configuration of the communicationsystem that performs visible light communication is not limited to thatillustrated in FIG. 5. For example, a configuration such as that shownin FIG. 31 may be used (see, for example, “IEEE 802.11-16/1499 r1”). InFIG. 31, a transmission signal is transmitted as a light signal in abaseband without being upconverted. That is, a device that transmits alight signal according to the present embodiment (that is, a devicehaving a light source) may have the configuration on the transmittingside shown in FIG. 31, and a terminal that receives an optical signalaccording to the present embodiment may have the configuration on thereceiving side shown in FIG. 31.

The configuration in FIG. 31 is described in further detail below. Asymbol mapping unit inputs transmission data and outputs a symbolsequence (ci) that performs mapping based on a modulation scheme.

A pre-equalizer receives the symbol sequence as an input, performspre-equalization processing on the symbol sequence to reduceequalization processing to be performed on the receiving side, andoutputs the resultant pre-equalized symbol sequence.

A Hermitian symmetry processing unit receives, as an input thereto, thepre-equalized symbol sequence, performs subcarrier allocation on thepre-equalized symbol sequence such that Hermitian symmetry is obtained,and outputs a resultant parallel signal.

An inverse (fast) Fourier transform unit receives a parallel signal asan input, performs inverse (fast) Fourier transform on the parallelsignal, and outputs a resultant inverse (fast) Fourier transformedsignal.

A parallel-serial and cyclic prefix adder receives, as an input, theinverse (fast) Fourier transformed signal, performs parallel-serialtransform, adds a cyclic prefix, and outputs a resultantsignal-processed signal.

A digital-to-analog converter receives, as an input, thesignal-processed signal, performs a digital-to-analog conversion, andoutputs a resultant analog signal. The analog signal is output as light,for example, from one or more LEDs.

Note that the pre-equalizer and the Hermitian symmetry processing unitmay not be provided. That is, the signal processing by the pre-equalizerand the Hermitian symmetry processing unit may not be performed.

A photodiode receives light as an input, and obtains a reception signalvia a TIA (Transimpedance Amplifier).

An analog-to-digital converter performs an analog-to-digital conversionon the received signal and outputs a resultant digital signal.

A cyclic prefix removal and serial-to-parallel converter receives, as aninput, the digital signal performs cyclic prefix removal, and thenperforms a serial-to-parallel conversion, and inputs a parallel signal.

A (fast) Fourier transform unit receives, as an input, the parallelsignal, performs (fast) Fourier transform, and outputs a resultant(fast) Fourier transformed signal.

A detection unit receives, as an input, the Fourier transformed signal,performs detection, and outputs a resultant reception symbol sequence.

A symbol demapper receives, as an input, the reception symbol sequence,performs demapping, and obtains a reception data sequence as a result.

Embodiment 8

FIG. 32 is a diagram illustrating an example of a configuration of acommunication system according to Embodiment 8. The communication systemin FIG. 32 includes a communication apparatus 3900, a terminal #1(3920_1), a terminal #2 (3920_2), a terminal #3 (3920_3), a base station#1, a base station #2, an AP #1, a network, a server, etc. Thecommunication apparatus 3900 described here may be installed, forexample, on a transportation vehicle (a train, a bus, an aircraft,etc.). In the present embodiment, it is assumed by way of example thatthe communication apparatus 3900 is installed on a train. Note that thebase station #1, the network, and the server may be collectivelyreferred to as an external system 3940_1. The AP #1, the network, andthe server may be collectively referred to as an external system 3940_2.The base station #2, the network, and the server may be collectivelyreferred to as an external system 3940_3.

Let it be assumed by way example that a train is traveling fromShin-Yokohama to Tokyo. The communication apparatus 3900 shown in FIG.32 is a communication apparatus installed in a train. The communicationapparatus 3900 in FIG. 32 includes a data selection unit 3901, atransmitter 3902, and an illumination 3903.

The transmitter 3902 performs processing for transmission on the datainput from the data selection unit 3901 thereby generating a modulatedsignal, and the illumination 3903 transmits the modulated signal aslight. Hereinafter, the light transmitted from the illumination 3903 isreferred to as a modulated light signal. The operations of thetransmitter 3902 and the illumination 3903 have been described inEmbodiment 1 to Embodiment 8, and thus a further detailed description isomitted. The transmitter 3902 and the illumination 3903 correspond to,for example, the transmitter 102 and the light source 104 in FIG. 6,FIG. 9, FIG. 13, FIG. 22, or FIG. 24.

Next, the operation of the data selection unit 3901 is described. To thedata selection unit 3901, location information indicating, for example,a traveling point, a traveling direction, and/or the like is input. Thelocation information may be traveling point information indicating atraveling point of a train on which the communication apparatus 3900 isinstalled, which is obtained by receiving a modulated signal from a GPS(Global Positioning Systems) satellite, or it may be locationinformation based on “information on a station that has been passed” or“a distance from a passed station or an elapsed time since the passing”.The traveling point information may be information transmitted from apredetermined system that manages the operation of the train, or may beinformation measured or obtained via another method.

The location information may further include traveling directioninformation related to the traveling direction of the train. The traintraveling direction information may be set in advance based on a diagramof the train on which the communication apparatus 3900 is installed, ormay be transmitted from the predetermined system that manages theoperation of the train. The traveling direction information may beobtained by calculation or may be obtained by another method. Theconfiguration of the location information is not limited to the examplesdescribed above.

Then, the data selection unit 3901 selects data to be transmitted fromthe illumination 3903 based on the location information described above,and outputs the selected data to the transmitter 3902. The data to beselected will be described later with reference to FIGS. 33 and 34.

The selected data is subjected to signal processing in the transmitter3902 and transmitted as a modulated light signal from the illumination3903. The transmitter 3902 performs signal processing such as errorcorrection coding, mapping, and/or the like thereby generating amodulated light signal. The transmitter 3902 outputs the resultantmodulated light signal to the illumination 3903.

The illumination 3903 controls the output of light and transmits themodulated light signal input from the transmitter 3902. The illumination3903 is, for example, an illumination apparatus installed in each traincar, or an illumination apparatus installed on each train seat, or thelike.

Note that the operation of the transmitter 3902 may be similar to thatof the transmitter 102, 103 or 1404 according to embodiments describedabove. The operation of the illumination 3903 may be similar to that ofthe light source 104 or 1406 according to the embodiments describedabove. Although in the present embodiment, the illumination 3903transmits a signal using light, the signal transmission medium is notmilted to light, and a signal may be transmitted using a radio wave.That is, the illumination 3903 is an example of a unit for realizingwireless transmission.

Next, an example of an operation of the terminal in FIG. 32 is describedin detail.

The terminal 3920_1 (the terminal #1) receives the modulated lightsignal transmitted from the illumination 3903 and obtains datatransmitted by the communication apparatus 3900 using the modulatedlight signal. A light-related configuration of the reception apparatusincluded in the terminal 39201 (the terminal #1) has been describedabove in Embodiment 1 to Embodiment 8, and thus a further descriptionthereof is omitted. For example, it corresponds to the terminal 150 inFIG. 6, the terminal 450 in FIG. 9, or the terminal 1050 in FIG. 13,FIG. 22, or FIG. 24.

The terminal 3920_1 (the terminal #1) may obtain data, for example, byconnecting to another communication system based on data obtained fromthe received modulated light signal. For example, the terminal 3920_1(the terminal #1) may access a server via the base station #1 and anetwork to obtain data from the server.

Similarly, the terminal 39202 (the terminal #2) receives a modulatedlight signal transmitted from the illumination 3903, and obtains datatransmitted by the communication apparatus 3900 using the modulatedlight signal. A light-related configuration of the reception apparatusincluded in the terminal 39202 (the terminal #2) has been describedabove in Embodiment 1 to Embodiment 8, and thus a further descriptionthereof is omitted. For example, it corresponds to the terminal 150 inFIG. 6, the terminal 450 in FIG. 9, or the terminal 1050 in FIG. 13,FIG. 22, or FIG. 24.

The terminal 3920_2 (the terminal #2) may obtain data, for example, byconnecting to another communication system based on data obtained fromthe received modulated light signal. For example, the terminal 3920_2(the terminal #2) may access the server via the base station #2 and anetwork to obtain data from the server.

Similarly, the terminal 39203 (the terminal #3) receives a modulatedlight signal transmitted from the illumination 3903, and obtains datatransmitted by the communication apparatus 900 using the modulated lightsignal. A light-related configuration of the reception apparatusincluded in the terminal 39203 (the terminal #3) has been describedabove in Embodiment 1 to Embodiment 8, and thus a further descriptionthereof is omitted. For example, it corresponds to the terminal 150 inFIG. 6, the terminal 450 in FIG. 9, or the terminal 1050 in FIG. 13,FIG. 22, or FIG. 24.

The terminal 3920_3 (the terminal #3) may obtain data, for example, byconnecting to another communication system based on data obtained fromthe received modulated light signal. For example, the terminal 3920_3(the terminal #3) may access the server via the base station #3 and anetwork to obtain data from the server.

Next, with reference to FIGS. 33 and 34, an example of data selected bythe data selection unit 3901 of the communication apparatus 3900 in FIG.32 and an example of a selection method are described. FIGS. 33 and 34each illustrate an example of data selected and output by the dataselection unit of the communication apparatus 3900 shown in FIG. 32.

In each of FIGS. 33 and 34, a horizontal axis indicates “places” wherethe train is running. Note that the places may indicate, for example,places on a train traveling route. However, the horizontal axis mayindicate “place” and “time (or elapsed time)”. In this case, a “morespecific place (traveling point)” of the train can be identified fromthe “place” and the “time (or elapsed time)”. Here, the elapsed time is,for example, a time elapsed since a time of passing a immediatelypreceding reference point (such as a station).

FIG. 33 and FIG. 34 each illustrate an example of a method in which thedata selection unit 3901 selects data related to a location ahead of acurrent train traveling point in a train traveling direction from aplurality of pieces of data. Hereinafter, the data related to thelocation ahead of the current location in the train traveling directionis also referred to as “approaching-location data”. A plurality of datafrom which data is to be selected by the data selection unit 3901 may bestored locally in the communication apparatus 3900, or may be stored inan external server accessible by the communication apparatus 3900 usinga communication function. In the present embodiment, the followingdescription is given, by way of example, for a case where the datarelated to the location is data of an advertisement group related to thelocation. However, the data related to the location is not limited tothe data of the advertisement group, but it may be any data such as dataof a map or weather related to the location.

Next, with reference to FIG. 33, an example is described in which anadvertisement group is transmitted in an up train traveling fromShin-Yokohama Station to Shinagawa Station.

As shown in FIG. 33, when the train is traveling in a section A fromShin-Yokohama Station to a point #1, the data selection unit 3901disposed in the communication apparatus 3900 in FIG. 32 selects, forexample, an advertisement group #A from data stored in the dataselection unit, and outputs the data of the advertisement group #A asselected data. Thus, when the train is traveling in the section A fromShin-Yokohama Station to the point #1, the illumination 3903 on thetrain transmits the data of the advertisement group #A using a modulatedlight signal.

When the train is traveling in a section B from the point #1 to a point#2, the data selection unit 3901 disposed in the communication apparatus3900 in FIG. 32 selects, for example, data of an advertisement group #Bfrom the data stored in the data selection unit, and outputs the data ofadvertisement group #B is as selected data. Thus, when the train istraveling in the section B from the point #1 to the point #2, theillumination 3903 in the train transmits the data of the advertisementgroup #B using a modulated light signal.

When the train is traveling in a section C from the point #2 toShinagawa Station, the data selection unit 3901 disposed in thecommunication apparatus 3900 in FIG. 32 selects, for example, data of anadvertisement group #C from the data stored in the data selection unit,and outputs the data of the advertisement group #C as selected data.Thus, when the train is traveling in the section C from the point #2 toShinagawa Station, the illumination 3903 on the train transmits the dataof the advertisement group #C using a modulated light signal.

Next, with reference to FIG. 34, an example is described in which anadvertisement group is delivered in an up train traveling from ShinagawaStation to Tokyo Station.

When the train is traveling in a section D from Shinagawa Station to apoint #3 as shown in FIG. 34, the data selection unit 3901 disposed inthe communication apparatus 3900 in FIG. 32 selects, for example, dataof an advertisement group #D from the data stored in the data selectionunit, and outputs the data of the advertisement group #D as selecteddata. Thus, when the train is traveling in the section D from ShinagawaStation to the point #3, the illumination 3903 on the train transmitsthe data of the advertisement group #D using a modulated light signal.

When the train is traveling in a section E from the point #3 to a point#4, the data selection unit 3901 disposed in the communication apparatus3900 in FIG. 32 selects, for example, data of an advertisement group #Efrom the data stored in the data selection unit, and outputs the data ofthe advertisement group #E as selected data. Thus, when the train istraveling in the section E from the point #3 to the point #4, theillumination 3903 on the train transmits the data of the advertisementgroup #E using a modulated light signal.

When the train is traveling in a section F from the point #4 to TokyoStation, the data selection unit 3901 disposed in the communicationapparatus 3900 in FIG. 32 selects, for example, data of an advertisementgroup #F from the data stored in the data selection unit, and outputsthe data of the advertisement group #F as selected data. When the trainis traveling in the section F from the point #4 to Tokyo Station, theillumination 3903 on the train transmits the data of the advertisementgroup #F using a modulated light signal.

Note that the method employed by the data selection unit 3901 to obtaindata of an advertisement group is not limited to the method in whichdata is obtained from the stored data including the data of theadvertisement group #A, the data of the advertisement group #B, the dataof the advertisement group #C, the data of the advertisement group #D,the data of the advertisement group #E, and the data of advertisementgroup #F. For example, the data selection unit 3901 of the communicationapparatus 3900 in FIG. 32 may have a communication function, and mayreceive, from an external server or the like, the data of theadvertisement group #A, the data of the advertisement group #B, the dataof the advertisement group #C, the data of the advertisement group #D,the data of the advertisement group #E, and/or the data of theadvertisement group #F.

For example, the advertisement group #A, the advertisement group #B, andthe advertisement group #C in FIG. 33 each do not include“advertisements related to Shin-Yokohama Station and/or its neighbors”and “advertisements related to stations that the train stopped at orpassed through before reaching Shin-Yokohama Station and/or theirneighbors”, but they each include “advertisements related to ShinagawaStation and/or its neighbors” or “advertisements related to stations,and/or their neighbors, the train will stop at or pass through afterleaving Shinagawa Station”. That is, the advertisement group #A, theadvertisement group #B, and the advertisement group #C each includeinformation on something related to places located ahead in thedirection in which the train is traveling. That is, the data selectionunit 3901 selects an advertisement group related to a location ahead ofthe current train traveling point in the traveling direction (that is,an approaching location-related advertisement group). However, theadvertisement group #A, the advertisement group #B, and theadvertisement group #C each may include an advertisement that does notfollow this rule, or an advertisement not much related to stations ortheir neighbors.

Similarly, the advertisement group #D, the advertisement group #E, andthe advertisement group #F in FIG. 34 each do not include“advertisements related to Shinagawa Station and/or its neighbors” and“advertisements related to stations that the trains stopped at or passedthrough before reaching Shinagawa Station, but they each includes“advertisements related to Tokyo Station and/or its neighbors” or“advertisements related to stations the train will stop at or passthrough after leaving Tokyo Station and/or their neighbors”. That is,the advertisement group #D, the advertisement group #E, and theadvertisement group #F each include information on something related toplaces located ahead in the direction in which the train is traveling.That is, the data selection unit 3901 selects an advertisement grouprelated to a location ahead of the current train traveling point in thetraveling direction (that is, an approaching location-relatedadvertisement group). However, the advertisement group #D, theadvertisement group #E, and the advertisement group #F may include anadvertisement that does not follow this rule, or an advertisement notmuch related to stations or their neighbors.

As described above, by switching data depending on the location of thetrain such that data such as an advertisement transmitted by thecommunication apparatus 3900 in FIG. 32 is switched to data such as anadvertisement more suitable for the traveling point and the travelingdirection of the train, it is possible to increase the possibility thata user using a terminal on the train can obtain desired data from thecommunication apparatus 3900 shown in FIG. 32. That is, by selecting anadvertisement group to be transmitted to terminals based on the currenttrain traveling point and the traveling direction, it becomes possibleto deliver the advertisement group having a time-dependent high uservalue to terminals of train passengers (users).

Data of an advertisement group may be information of the advertisementitself, or information on an access destination from which to obtaininformation of the advertisement (for example, a URL (Uniform ResourceLocator)). The information of the advertisement itself is, for example,data forming the advertisement itself (for example, characters, images,audio data, audio data). The data of the advertisement group may haveinformation on one or more advertisements. In the above description, itis assumed by way of example that data selected by the data selectionunit 3901 is an advertisement group. However, the data is not limited tothe advertisement group. For example, the data may be map information ona location in the traveling direction (for example, an area around astation located ahead in the traveling direction) or informationspecific to a location (information specific to a place). However, theinformation is not limited to this.

Two different advertisement groups (for example, the advertisement group#A and the advertisement group #B) may include the same advertisement ordifferent advertisements. For example, in FIG. 33, information of thesame advertisement may exist in the advertisement group #A and theadvertisement group #B. That is, the information of the sameadvertisement may be included in two different advertisement groups (forexample, the advertisement group #A and advertisement group #B). On theother hand, for example, the advertisement group #A and theadvertisement group #B may include different advertisement information.That is, two different advertisement groups may contain information ofdifferent advertisements. Note that this relationship is not limited toadvertisements.

The configuration of the transmission frame of the advertisement groupstransmitted by the communication apparatus 3900 in FIG. 32 is notlimited to those shown in FIGS. 33 and 34.

Next, FIG. 35 illustrates another example, different from that shown inFIG. 33, of data selected and output by the data selection unit 3901 ofthe communication apparatus 3900 in FIG. 32. That is, FIG. 35illustrates another example different from the example shown in FIG. 33,in which advertisement groups are delivered in an up train travelingfrom Shin-Yokohama Station to Shinagawa Station. In the exampledescribed above with reference to FIG. 33, a plurality of advertisementgroups are transmitted in associated corresponding sections withoutoverlapping. In the example in FIG. 35, a plurality of advertisementgroups are transmitted in at least partially overlapping sections.

In FIG. 35, as in FIG. 33, a horizontal axis indicates “places” where atrain is running. Note that the places may indicate, for example, placeson a train traveling route. Note that the horizontal axis may indicate“place” and “time (or elapsed time)”. In this case, a “more specificplace (traveling point)” of the train can be identified from the “place”and the “time (or elapsed time)”. Here, the elapsed time is, forexample, a time elapsed since a time of passing an immediately precedingreference point (such as a station).

As shown in FIG. 35, when the train is traveling in a section A fromShin-Yokohama Station to a point #1, the data selection unit 3901disposed in the communication apparatus 3900 in FIG. 32 selects, forexample, an advertisement group #A from data stored in the dataselection unit, and outputs the data of the advertisement group #A asselected data. Thus, when the train is traveling in the section A fromShin-Yokohama Station to the point #1, the illumination 3903 in thetrain transmits the data of the advertisement group #A using a modulatedlight signal.

When the train is traveling in a section B from the point #1 to a point#2, the data selection unit 3901 disposed in the communication apparatus3900 in FIG. 32 selects, for example, data of an advertisement group #Bfrom the data stored in the data selection unit, and outputs the data ofadvertisement group #B is as selected data. Thus, when the train istraveling in the section B from the point #1 to the point #2, theillumination 3903 in the train transmits the data of the advertisementgroup #B using a modulated light signal.

When the train is traveling in a section C from the point #2 toShinagawa Station, the data selection unit 3901 disposed in thecommunication apparatus 3900 in FIG. 32 selects, for example, data of anadvertisement group #C from the data stored in the data selection unit3901, and outputs the data of the advertisement group #C as selecteddata. Thus, when the train is traveling in the section C from the point#2 to Shinagawa Station, the illumination 3903 in the train transmitsthe data of the advertisement group #C using a modulated light signal.

When the train is traveling in a section W from Shin-Yokohama Station toShinagawa Station, the data selection unit 3901 disposed in thecommunication apparatus 3900 in FIG. 32 selects, for example, data of anadvertisement group #W from the data stored in the data selection unit3901, and outputs the data of the advertisement group #W as selecteddata. Thus, when the train is traveling in the section W fromShin-Yokohama Station to Shinagawa Station, the illumination 3903 in thetrain transmits the data of the advertisement group #C using a modulatedlight signal.

When the train is traveling in a section X from Shin-Yokohama Station toa point #15, the data selection unit 3901 disposed in the communicationapparatus 3900 in FIG. 32 selects, for example, data of an advertisementgroup #X from the data stored in the data selection unit 3901, andoutputs the data of the advertisement group #X as selected data. Thus,when the train is traveling in the section X from Shin-Yokohama Stationto the point #15, the illumination 3903 in the train transmits the dataof the advertisement group #X using a modulated light signal.

When the train is traveling in a section Y from a point #11 to a point#13, the data selection unit 3901 disposed in the communicationapparatus 3900 in FIG. 32 selects, for example, data of an advertisementgroup #Y from the data stored in the data selection unit 3901, andoutputs the data of the advertisement group #Y as selected data. Thus,when the train is traveling in the section Y from the point #11 to thepoint #13, the illumination 3903 in the train transmits the data of theadvertisement group #Y using a modulated light signal.

When the train is traveling in a section Z from a point #12 to a point#14, the data selection unit 3901 disposed in the communicationapparatus 3900 in FIG. 32 selects, for example, data of an advertisementgroup #Z from the data stored in the data selection unit 3901, andoutputs the data of the advertisement group #Z as selected data. Thus,when the train is traveling in the section Z from the point #12 to thepoint #14, the illumination 3903 in the train transmits the data of theadvertisement group #Z using a modulated light signal.

Note that the data selection unit 3901 in the communication apparatus3900 in FIG. 32 may select data of one or more advertisement groups fromthe data stored in the data selection unit 3901 depending on a placewhere the train is traveling and may output the selected one or moreadvertisement groups as selected data. For example, when the train istraveling in the section from the point #12 to the point #13, the dataselection unit 3901 in the communication apparatus 3900 in FIG. 32selects, from the data stored in the data selection unit 3901, the dataof the advertisement group #B, the data of the advertisement group #W,the data of the advertisement group #X, the data of the advertisementgroup #Z, and the data of the advertisement group #Y and outputs them asselected data. Thus, when the train is traveling in the section from thepoint #12 to the point #13, the communication apparatus 3900 transmitsthe data of the advertisement group #B, the data of the advertisementgroup #W, the data of the advertisement group #X, the data of theadvertisement group #Z, and the data of the advertisement group #Y usinga modulated light signal.

That is, when the current traveling point belongs simultaneously to aplurality of sections overlapping at least partly, the data selectionunit 3901 in FIG. 32 may select a plurality of advertisement groupsrespectively associated with the plurality of sections to which thecurrent traveling point belongs.

Note that the method employed by the data selection unit 3901 to obtaindata of an advertisement group is not limited to the method in which theadvertisement group #A, the data of the advertisement group #B, the dataof the advertisement group #C, the data of the advertisement group #W,the data of the advertisement group #X, the data of the advertisementgroup #Y, and/or the data of the advertisement group #Z is obtained fromthe stored data. For example, the data selection unit 3901 of thecommunication apparatus 3900 in FIG. 32 may have a communicationfunction, and may receive the data of the advertisement group #A, thedata of the advertisement group #B, the data of the advertisement group#C, the data of the advertisement group #W, the data of theadvertisement group #X, the data of the advertisement group #Y, and/orthe data of the advertisement group #Z from an external server or thelike.

<Modifications>

FIG. 36 shows a modification of the configuration, different from thatshown in FIG. 32, of the communication system according to the presentembodiment. In FIG. 36, elements similar in operation to those shown inFIG. 32 are denoted by similar reference numerals. These elements havebeen already described above, and thus a further description thereof isomitted.

The configuration shown in FIG. 36 is different from that shown in FIG.32 in that time information is input to the data selection unit 3901 ofthe communication apparatus 3900. That is, in addition to locationinformation, time information is also input to the data selection unit3901 in FIG. 36, and the data selection unit 3901 selects data based onthe location information and the time information, and outputs it asselected data. The location information is as described above withreference to FIG. 32, and the time information is, for example,information indicating the current time.

Next, an example of an operation of the data selection unit 3901 shownin FIG. 36 is described with reference to FIG. 37 and FIG. 38. FIGS. 37and 38 illustrate examples of data selected and output by the dataselection unit 3901 of the communication apparatus 3900 shown in FIG.36.

In each of FIGS. 37 and 38, a horizontal axis indicates “places” wherethe train is running. Note that the places may indicate, for example,places on a train traveling route. Note that the horizontal axis mayindicate “place” and “elapsed time”. In this case, a “more specificplace (traveling point)” of the train can be identified from the “place”and the “elapsed time”. Here, the elapsed time is a time elapsed sincethe time of passing the immediately preceding reference point (such as astation). In each of FIGS. 37 and 38, a vertical axis represent time(current time). That is, the upper part and the lower part in each ofFIG. 37 and FIG. 38 respectively show examples of set of advertisementgroups transmitted in trains traveling along the same traveling route indifferent time zones #1 and #2. The time zone #2 is later in time thanthe time zone #1.

FIGS. 37 and 38 each illustrate an example of a method in which the dataselection unit 3901 selects, from a plurality of pieces of data, datarelated to locations ahead of the current traveling point of the trainin the traveling direction based on the traveling point of the train,the traveling direction, and the current time. A plurality of data fromwhich data is to be selected by the data selection unit 3901 may bestored locally in the communication apparatus 3900, or may be stored inan external server accessible by the communication apparatus 3900 usinga communication function. In the following description of the presentembodiment, an explanation is given by way of example for a case wherethe data related to the location is an advertisement group related tothe location. However, the data related to the location is not limitedto the advertisement group, but it may be any data such as a map orweather related to the location.

Next, an example of a manner of transmitting an advertisement group inan up train traveling from Shin-Yokohama Station to Shinagawa Station intime zones #1 and #2 is described with reference to FIG. 37.

<Time Zone #1>

When the current time is within the time zone #1 and the train istraveling in a section A from Shin-Yokohama Station to a point #1, thedata selection unit 3901 in the communication apparatus 3900 shown inFIG. 36 selects, for example, data of an advertisement group #A from thedata stored in the data selection unit 3901 and outputs the data of theadvertisement group #A as selected data. Thus, when the train istraveling in the section A from Shin-Yokohama Station to the point #1and in the time zone #1, the illumination 3903 in the train transmitsthe data of the advertisement group #A using a modulated light signal.Note that the data of the advertisement group #A is data of anadvertisement group suitable for the time zone #1.

When the current time is within the time zone #1 and the train istraveling in a section B from the point #1 to a point #2, the dataselection unit 3901 in the communication apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #B from the datastored in the data selection unit 3901 and outputs the data of theadvertisement group #B as selected data. Thus, when the train istraveling in the section B from the point #1 to the point #2 in the timezone #1, the illumination 3903 in the train transmits the data of theadvertisement group #B using a modulated light signal. Note that thedata of the advertisement group #B is data of an advertisement groupsuitable for the time zone #1.

When the current time is within the time zone #1 and the train istraveling in a section C from the point #2 to Shinagawa Station, thedata selection unit 3901 in the communication apparatus 3900 shown inFIG. 36 selects, for example, data of an advertisement group #C from thedata stored in the data selection unit 3901 and outputs the data of theadvertisement group #C as selected data. Thus, in the communicationapparatus 3900, when the train is traveling in the section C from thepoint #2 to Shinagawa Station, the illumination 3903 in the traintransmits the data of the advertisement group #C using a modulated lightsignal. Note that the data of the advertisement group #B is data of anadvertisement group suitable for the time zone #1.

Note that the data selection unit 3901 gets to know, from the timeinformation, that the current time is within the time zone #1, and getsto know the current traveling point from the location information.

<Time Zone #2>

When the current time is within the time zone #2 and the train istraveling in a section N from Shin-Yokohama Station to a point #3, thedata selection unit 3901 in the communication apparatus 3900 shown inFIG. 36 selects, for example, data of an advertisement group #N from thedata stored in the data selection unit 3901 and outputs the data of theadvertisement group #N as selected data. Thus, when the train istraveling in the section N from Shin-Yokohama Station to the point #3 inthe time zone #2, the illumination 3903 in the train transmits the dataof the advertisement group #N using a modulated light signal. Note thatthe data of the advertisement group #N is data of an advertisement groupsuitable for the time zone #2.

When the current time is within the time zone #2 and the train istraveling in a section O from the point #3 to a point #4, the dataselection unit 3901 in the communication apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #O from the datastored in the data selection unit 3901 and outputs the data of theadvertisement group #O as selected data. Thus, when the train istraveling in the section O from the point #3 to the point #4 in the timezone #2, the illumination 3903 in the train transmits the data of theadvertisement group #O using a modulated light signal. Note that thedata of the advertisement group #O is data of an advertisement groupsuitable for the time zone #2.

When the current time is within the time zone #2 and the train istraveling in a section P from the point #4 to Shinagawa Station, thedata selection unit 3901 in the communication apparatus 3900 shown inFIG. 36 selects, for example, data of an advertisement group #P from thedata stored in the data selection unit 3901 and outputs the data of theadvertisement group #P as selected data. Thus, when the train istraveling in the section P from the point #4 to Shinagawa Station, theillumination 3903 in the train transmits the data of the advertisementgroup #P using a modulated light signal. Note that the data of theadvertisement group #P is data of an advertisement group suitable forthe time zone #2.

Note that the data selection unit 3901 gets to know, from the timeinformation, that the current time is within the time zone #2, and getsto know the current traveling point # from the location information.

Note that, for example, the advertisement group #A, the advertisementgroup #B, and the advertisement group #C, the advertisement group #N,the advertisement group #O, and the advertisement group #P in FIG. 37each do not include “advertisements related to Shin-Yokohama Stationand/or its neighbors” and “advertisements related to stations and/or itsneighbors that the train stopped at or passed through beforeShin-Yokohama Station”, but they each have “advertisements related toShinagawa Station and/or its neighbors” or “advertisements related tostations the train will stop at or pass through after leaving ShinagawaStation and/or related to their neighbors”. That is, the advertisementgroup #A, the advertisement group #B, the advertisement group #C, theadvertisement group #N, the advertisement group #O, and theadvertisement group #P each include information on something related toplaces located ahead in the direction in which the train is traveling.That is, the data selection unit 3901 selects an advertisement grouprelated to a location ahead of the current train traveling point in thetraveling direction (that is, an approaching location-relatedadvertisement group). However, the advertisement group #A, theadvertisement group #B, the advertisement group #C, the advertisementgroup #N, the advertisement group #O, and the advertisement group #P mayinclude an advertisement that does not follow this rule, or anadvertisement not much related to stations or their neighbors.

Next, with reference to FIG. 38, examples are described in whichadvertisement groups are transmitted in up trains traveling fromShinagawa Station to Tokyo Station in the time zone #1 and time zone #2.

<Time Zone #1>

In FIG. 38, when the current time is within the time zone #1 and thetrain is traveling in a section D from Shin-Yokohama Station to a point#11, the data selection unit 3901 in the transmission apparatus 3900shown in FIG. 36 selects, for example, data of an advertisement group3901 from the data stored in the data selection unit 3901 and outputsthe data of the advertisement group #D as selected data. Thus, when thetrain is traveling in the section D from Shinagawa Station to the point#11, the illumination 3903 in the train transmits the data of theadvertisement group #D using a modulated light signal. Note that thedata of the advertisement group #D is data of an advertisement groupsuitable for the time zone #1.

When the current time is within the time zone #1 and the train istraveling in a section E from the point #11 to a point #12, the dataselection unit 3901 in the transmission apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #E from the datastored in the data selection unit 3901 and output the data of theadvertisement group #E as selected data. Thus, when the train istraveling in the section E from the point #11 to the point #12 in thetime zone #1, the illumination 3903 in the train transmits the data ofthe advertisement group #E using a modulated light signal. Note that thedata of the advertisement group #E is data of an advertisement groupsuitable for the time zone #1.

When the current time is within the time zone #1 and the train istraveling in a section F from the point #12 to Tokyo Station, the dataselection unit 3901 in the transmission apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #F from the datastored in the data selection unit 3901 and outputs the data of theadvertisement group #F as selected data. Thus, when the train istraveling in the section F from the point #12 to Tokyo in the time zone#1, the illumination 3903 in the train transmits the data of theadvertisement group #F using a modulated light signal. Note that thedata of the advertisement group #F is data of an advertisement groupsuitable for the time zone #1.

Note that the data selection unit 3901 gets to know, from the timeinformation, that the current time is within the time zone #1, and getsto know the current traveling point from the location information.

<Time Zone #2>

When the current time is within the time zone #2 and the train istraveling in a section Q from Shinagawa Station to a point #13, the dataselection unit 3901 in the transmission apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #Q from the datastored in the data selection unit 3901 and outputs the data of theadvertisement group #Q as selected data. Thus, when the train istraveling in the section Q from Shinagawa Station to the point #13 inthe time zone #2, the illumination 3903 in the train transmits the dataof the advertisement group #Q using a modulated light signal.

When the current time is within the time zone #2 and the train istraveling in a section R from the point #13 to a point #14, the dataselection unit 3901 in the transmission apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #R from the datastored in the data selection unit 3901 and outputs the data of theadvertisement group #R as selected data. Thus, when the train istraveling in the section R from the point #13 to the point #14 in thetime zone #2, the illumination 3903 in the train transmits the data ofthe advertisement group #R using a modulated light signal. Note that thedata of the advertisement group #R is data of an advertisement groupsuitable for the time zone #2.

When the current time is within the time zone #2 and the train istraveling in a section S from the point #14 to Tokyo Station, the dataselection unit 3901 in the transmission apparatus 3900 shown in FIG. 36selects, for example, data of an advertisement group #S from the datastored in the data selection unit 3901 and outputs the data of theadvertisement group #S as selected data. Thus, when the train istraveling in the section S from the point #14 to Tokyo Station in thetime zone #2, the illumination 3903 in the train transmits the data ofthe advertisement group #S using a modulated light signal. Note that thedata of the advertisement group #S is data of an advertisement groupsuitable for the time zone #2.

Note that the data selection unit 3901 gets to know, from the timeinformation, that the current time is within the time zone #2, and getsto know the current traveling point # from the location information.

Note that the method employed by the data selection unit 3901 to obtaindata of an advertisement group is not limited to the method in which thedata of the advertisement group #A, the data of the advertisement group#B, the data of the advertisement group #C, the data of theadvertisement group #D, the data of the advertisement group #E, the dataof the advertisement group #F, the data of the advertisement group #N,the data of the advertisement group #O, the data of the advertisementgroup #P, the data of the advertisement group #Q, the data of theadvertisement group #R, and/or the data of the advertisement group isobtained from the stored data. For example, the data selection unit 3901of the communication apparatus 3900 in FIG. 36 may have a communicationfunction, and may acquire, from an external server or the like, the dataof the advertisement group #A, the data of the advertisement group #B,the data of the advertisement group #C, the data of the advertisementgroup #D, the data of the advertisement group #E, the data of theadvertisement group #F, the data of the advertisement group #N, the dataof the advertisement group #O, the data of the advertisement group #P,the data of the advertisement group #Q, the data of the advertisementgroup #R, and/or the data of the advertisement group.

Note that the advertisement group #D, the advertisement group #E, theadvertisement group #F, the advertisement group #Q, the advertisementgroup #R, and the advertisement group #S, in FIG. 38 each do not include“advertisements related to Shinagawa Station and/or its neighbors” and“advertisements related to stations that the train stopped at or passedthrough before Shinagawa Station” and/or related to their neighbors, butthey each includes “advertisements related to Tokyo Station and/or itsneighbors” or “advertisements related to stations the train will stop ator pass through after leaving Tokyo Station and/or their neighbors”.That is, the advertisement group #D, the advertisement group #E, theadvertisement group #F, the advertisement group #Q, the advertisementgroup #R, and the advertisement group #S each include information onsomething related to places located ahead in the direction in which thetrain is traveling. That is, the data selection unit 3901 selects anadvertisement group related to a location ahead of the current traintraveling point in the traveling direction (that is, an approachinglocation-related advertisement group). However, the advertisement group#D, the advertisement group #E, the advertisement group #F, theadvertisement group #Q, the advertisement group #R, and theadvertisement group #S each may include an advertisement that does notfollow this rule, or an advertisement not much related to stations ortheir neighbors.

Let it be assumed, by way of example, that in FIGS. 37 and 38 the timezone #1 is “from 10 o'clock to 12 o'clock” and the time zone #2 is “from16 o'clock to 18 o'clock”. Let it be further assumed here, by way ofexample, that the advertisement group delivered in the time zone #1 isan advertisement group related to a lunch restaurant, and theadvertisement group delivered in the time zone #2 is an advertisementgroup related to a dinner restaurant. As described above, by selectingan advertisement group to be transmitted to terminals based on the timezone including the current time, it becomes possible to deliver theadvertisement group having a time-dependent high user value to terminalsof train passengers (users). Thus, users using terminals shown in FIG.36 in a train can obtain information more suitable for the current time.

As described above, by switching data such that data such as anadvertisement transmitted by the communication apparatus 3900 in FIG. 36is switched to data such as an advertisement more suitable for thetraveling point and the traveling direction of the train and suitablefor the time zone, depending on the traveling point of the train, thetraveling direction, and the time zone to which the current timebelongs, it is possible to increase the possibility that a user using aterminal on the train can obtain desired data from the communicationapparatus 3900 shown in FIG. 36.

Data of an advertisement group may be information of the advertisementitself, or information on an access destination from which to obtaininformation of the advertisement (for example, a URL (Uniform ResourceLocator)). The information of the advertisement itself is, for example,data forming the advertisement itself (for example, characters, images,audio data, audio data). The data of the advertisement group may haveinformation on one or more advertisements. In the above description, itis assumed by way of example that data selected by the data selectionunit 3901 is an advertisement group. However, the data is not limited tothe advertisement group. For example, the data may be map information ona location in the traveling direction (for example, an area around astation located ahead in the traveling direction) or informationspecific to a location (information specific to a place). However, theinformation is not limited to this.

Two different advertisement groups (for example, the advertisement group#A and the advertisement group #B) may include the same advertisement ordifferent advertisements. For example, in FIG. 37, information of thesame advertisement may exist in the advertisement group #A and theadvertisement group #B. That is, the information of the sameadvertisement may be included in two different advertisement groups (forexample, the advertisement group #A and advertisement group #B). On theother hand, for example, the advertisement group #A and theadvertisement group #B may include different advertisement information.That is, two different advertisement groups may contain information ofdifferent advertisements. Note that this relationship is not limited toadvertisements.

The configuration of the transmission frame of the advertisement groupstransmitted by the communication apparatus 3900 in FIG. 36 is notlimited to those shown in FIGS. 37 and 38, and the setting of the timezones is not limited to the examples shown in FIG. 37 and FIG. 38. FIG.39 shows another example of data selected and output by the dataselection unit 3901 disposed in the communication apparatus 3900 shownin FIG. 36.

FIG. 39 illustrates another example, different from the example shown inFIG. 37, in which advertisement groups are distributed in an up traintraveling from Shin-Yokohama Station to Shinagawa Station in time zones#3, #4, and #5. In FIG. 39, as in FIG. 37, a horizontal axis indicates“places” where the train is running. Note that the horizontal axis mayindicate “place” and “elapsed time”. In this case, a “more specificplace (traveling point)” of the train can be identified from the “place”and the “elapsed time”. Here, the elapsed time is a time elapsed sincethe time of passing the immediately preceding reference point (such as astation). In FIG. 39, a vertical axis indicates time (current time). Forexample, the time zone is divided into three zones and named as a timezone #3, a time zone #4, and a time zone #5.

FIG. 39 illustrates an example of a manner of transmitting advertisementgroups in three different time zones #3, #4 and #5. In the time zone #3,the advertisement group #A, the advertisement group #B, and theadvertisement group #C are transmitted in sections #A, #B, and #C,respectively, as in the case shown in the upper part of FIG. 37. Themanner of transmitting advertisement groups in the time zone #3 is thesame as that in the time zone #1 shown in FIG. 37, and thus a furtherdetailed description thereof is omitted. In the time zone #4, theadvertisement group #N, the advertisement group #O, and theadvertisement group #P are transmitted in sections #N, #O and #P,respectively, as in the case shown in the lower part of FIG. 37. Themanner of transmitting advertisement groups in the time zone #4 is thesame as that in the time zone #2 shown in FIG. 37, and thus a furtherdetailed description thereof is omitted. In the time zone #5, as in FIG.35, the advertisement group #A, the advertisement group #B, theadvertisement group #C, the advertisement group #W, the advertisementgroup #X, the advertisement group #Y, and the advertisement group #Z aretransmitted in sections #A, #B, #C, #W, #X, #Y, and #Z, respectively.The transmission manner in the time zone #5 has already been describedabove with reference to FIG. 35, and thus a further detailed descriptionthereof is omitted.

FIG. 39 illustrates an example of a configuration of a transmissionframe of an advertisement group transmitted by the communicationapparatus 3900 in FIG. 36, but the frame configuration is not limited tothis.

As described above, in the present embodiment, the communicationapparatus installed on a train or the like switches an advertisementgroup transmitted to a terminal based on information on a place and moreparticularly on a traveling point of the train or the like, a travelingdirection, a time, and/or the like, and thus a user, who iscommunicating with this transmission apparatus, can obtain more suitableinformation.

The present embodiment has been described above assuming by way ofexample that trains are up trains. In a case where trains are downtrains, the traveling direction is different from that of the up trains,and advertisement groups transmitted in down trains are different fromthose transmitted in up trains even in the same sections and/or in thesame time zones. For example, in a down train traveling from TokyoStation to Shinagawa Station on the route shown in FIG. 34,advertisement groups transmitted are different from the advertisementgroup #F which is transmitted in up trains in the section F from TokyoStation to the point #4. The approaching location-related advertisementgroups transmitted do not include “advertisements related to TokyoStation and nearby locations” and “advertisements related to stationswhere the train stopped (or passed) before Tokyo Station andadvertisements related to nearby locations”, but they include“advertisements related to Shinagawa Station and nearby locations”and/or “advertisements related to stations where the train will stop (orpass) after Shinagawa Station and advertisements related to nearbylocations”.

In the present embodiment, the communication apparatus 3900 selectsapproaching-location data from a plurality of pieces of data based onthe traveling point of the train, the traveling direction, and/or thecurrent time. This makes it possible to transmit data havingtime-dependent high value for users to terminals of train passengers(users).

In the present embodiment, the communication apparatus 3900 isinstalled, by way of example, on a train. However, the communicationapparatus 3900 may be installed on another type of transportationvehicle. For example, a communication apparatus 3900 may be installed ona transportation vehicle such as a bus, an aircraft, or the like, andthe communication apparatus 3900 may transmit transmission destinationdata to terminals of passengers (users) of the transportation vehicle.

The communication apparatus 3900 may incorporate information indicatingthe traveling point and/or the current time into the data transmittedfrom the illumination 3903. This enables the terminal to obtain thetraveling point and/or the current time from the received data.

Embodiment 9

FIGS. 40 and 41 are diagrams each illustrating an example of aconfiguration employed in a case where the communication apparatus 3900in FIGS. 32 and 36 further uses information (location information) on aninstallation location of each illumination 3903. In this configuration,location information associated with each illumination is input to thedata selection unit 3901 in FIG. 40 and FIG. 41.

In FIGS. 40 and 41, illuminations 3903_1, 39032, and 3903_3 transmitinformation on their respective installation locations (locationinformation) to a data selection unit 3901. For example, in a case wherethe illumination 3903 is an illumination apparatus installed on aceiling of each train car, the location information of the illumination3903 may include a train car number of the train on which theillumination 3900 is installed (for example, when the train car is ann-th train car, the train car number may be n and n is, for example, anatural number). Note that the illumination 3903 may transmit itsidentification information, instead of the location information of theillumination 3903, to the data selection unit 3901. This makes itpossible for the terminal to obtain the information on the train carnumber of the train car where the terminal is located.

The data selection unit 3901 manages the location information byassociating each piece of location information (or identificationinformation) of the illumination 3903 to particular information. Forexample, as described below with reference to “Example 5” and “Example6”, the location information is managed such that the locationinformation of the illumination 3903 is associated with particularinformation. Also note that the following Example 5 and Example 6 may beimplemented in combination.

Example 5

The data selection unit 3901 manages information such that theinstallation location (for example, the train car number) of eachillumination 3903 is associated with connection information, forexample, an SSID, assigned to a base station (or an AP) to whichterminals in the train car are to be connected. For example, in FIG. 40,the illumination 3903_1 (the illumination #1) is associated with an SSIDof a base station relatively close to this illumination #1 (for example,a base station located in the same train car), that is, the base station#1, in this case. Similarly, the illumination 3903_1 (an illumination#2) is associated with an SSID of an AP relatively close to theillumination #2 (for example, an AP located in the same train car), thatis, the AP #1, in this case. An illumination 3903_1 (an illumination #3)is associated with an SSID of a base station relatively close to theillumination #3 (for example, a base station located in the same traincar), that is, the base station #2, in this case.

When the data selection unit 3901 selects an advertisement group (data)to be transmitted using a modulated light signal from the illumination3903 according to Embodiment 8, the data selection unit 3901 selects anSSID associated with the installation location of the illumination 3903and the data selection unit 3901 incorporates the selected SSID into thedata. That is, the data transmitted from the illumination 3903 to theterminal 3920 includes the SSID of the base station (or the AP)associated with the installation location of the illumination 3903. Thismakes it possible for terminals 3920 of passengers (users) in respectivetrain cars of the train to be connected to different SSIDs depending onthe train cars. For example, in FIG. 40, the terminal 39201 (theterminal #1) receives the SSID of the base station #1 from theillumination #1, and thus the terminal #1 is connected to the basestation #1. Similarly, the terminal 39202 (the terminal #2) receives theSSID of the AP #1 from the illumination #2, and thus the terminal #2 isconnected to the AP #1. Similarly, the terminal 3920_3 (the terminal #3)receives the SSID of the base station #2# from the illumination #3, andthus the terminal #3 is connected to the base station #2.

Example 6

The data selection unit 3901 manages information such that theinstallation location (for example, the train car number) of eachillumination 3903 is associated with an advertisement group to betransmitted to terminals in this train car. For example, in FIG. 40, theillumination 39031 (the illumination #1) is associated with anadvertisement group to be transmitted to the terminal 39201 (theterminal #1) in a train car in which the illumination #1 is installed.Similarly, the illumination 39032 (the illumination #2) is associatedwith an advertisement group to be transmitted to the terminal 3920_2(the terminal #2) in a train car in which the illumination #2 isinstalled. The illumination 39033 (the illumination #3) is associatedwith an advertisement group to be transmitted to the terminal 3920_3(the terminal #3) in a train car in which the illumination #3 isinstalled.

The data selection unit 3901 selects approaching location-relatedadvertisement groups based on the train traveling direction, thetraveling point, and/or the current time according to Embodiment 8, andfurther selects, for each illumination 3903, an advertisement groupassociated with the installation location of the illumination 3903 fromthe selected approaching location-related advertisement groups. That is,approaching location-related advertisement groups are selected based onthe train traveling direction, the traveling point, and/or the currenttime, and further an advertisement group associated with theinstallation location of the illumination 3903 is selected based on theinstallation location (for example, the train car number) of theillumination 3903 from the approaching location-related advertisementgroups and the selected advertisement group is transmitted to terminals3920 in the corresponding one of the train cars of the train. This makesit possible for the communication apparatus 3900 to transmit, toterminals 3920 of passengers (users) on the train, advertisement groupsrelated to approaching locations such that the transmitted advertisementgroup is different depending on the train car.

Note that the information on the installation location of theillumination 3903 is not limited to the train car number of the train.For example, the illumination 3903 may be an illumination apparatusinstalled above each seat, and the installation location of theillumination 3903 may be indicated by a seat number of the train. Inthis case, the communication apparatus 3900 can transmit, to terminals3920 of passengers (users) on the train, advertisement groups differentfor each seat.

In the present embodiment, the communication apparatus 3900 isinstalled, by way of example, on a train. However, the communicationapparatus 3900 may be installed on another type of transportationvehicle. For example, a communication apparatus 3900 may be installed ona transportation vehicle such as a bus, an aircraft, or the like, andthe communication apparatus 3900 may transmit data to terminals 3920 ofpassengers (users) of the transportation vehicle. The communicationapparatus 3900 may incorporate information on a traveling point and/or acurrent time into data transmitted from the light source 3903. In thiscase, the terminal 3920 can obtain the travel location and/or thecurrent time from the received data.

The communication apparatus may transmit a modulated light signalincluding both information on an advertisement or the like andinformation on an SSID.

Embodiment 10

The previous embodiments relate to vehicles, and directions in which thevehicles are traveling can be easily estimated. In Embodiment 10, incontrast, an example is described in which the communication apparatus3900 transmits, to a pedestrian (a user) having a terminal, informationsuitable from the point of view of a traveling direction of thepedestrian using a modulated light signal.

FIG. 42 illustrates an example in which the communication apparatus 3900transmits, to terminals, a modulated light signal including anadvertisement group related to a west gate direction of a station and anadvertisement group related to an east gate direction.

In FIG. 42, the communication apparatus 3900 is installed, for example,on a road, and transmits from the illumination 3903 a modulated lightsignal including an advertisement group related to the west gatedirection or east gate direction of the station. On the other hand, theterminals each has an acceleration sensor and/or a gyro sensor. When aterminal is moved, for example, to the right (in the direction to thewest gate of the station in FIG. 42), the terminal displays informationrelated to the west gate direction on its screen. In a case where theterminal is moved to the left (in the direction to the east gate of thestation in FIG. 42), the terminal displays information related to theeast gate direction on the screen. The manner of moving the terminal isnot limited to these examples. For example, when the terminal is rotatedleft, the terminal displays information on the direction of the westgate on the screen, and when the terminal is rotated right, the terminalInformation on the east gate direction may be displayed on the screen.

Thus, the communication apparatus 3900 associates data such that theadvertisement group (data) related to the west gate direction of thestation is associated to operation information indicating that thisadvertisement group is displayed when the terminal 3920 is moved in thedirection to the west gate. On the other hand, the advertisement group(data) related to the east gate direction of the station is associatedto operation information indicating that this advertisement group isdisplayed when the terminal 3920 is moved in the direction to the westgate. The terminal 3920 receives this modulated light signal, and storesadvertisement information and operation information related to the westgate direction or east gate direction of the station included in thereceived modulated light signal.

When a pedestrian (a user) moves (for example, tilts) the terminal 3920in the direction to the west gate of the station (to the right in FIG.42), the terminal 3920 displays an advertisement group related to thewest gate direction of the station associated with the operationinformation related to this operation. When a pedestrian (a user) moves(for example, tilts) the terminal 3920 in the direction to the east gateof the station (to the left in FIG. 42), the terminal 3920 displays anadvertisement group related to the east gate direction of the stationassociated with the operation information related to this operation. Themovement direction (or the tilt direction) of the terminal 3920 may bedetected by the acceleration sensor and/or the gyro sensor provided onthe terminal 3920.

The manner of moving the terminal 3920 is not limited to these examples.For example, a pedestrian rotates the terminal 3920 to the right, theterminal 3920 may display an advertisement group related to the westgate direction of the station. When the pedestrian rotates the terminal3920 to the left, the terminal 3920 may display an advertisement grouprelated to the east gate direction of the station.

Next, an example is described in which communication apparatuses 3900are installed in a commercial facility having a plurality of floors.

In this case, a communication apparatus 3900 is installed on each floorand transmits, from an illumination 3903, a modulated light signalincluding advertisement groups related to upper and lower floors. Tothis end, the communication apparatus 3900 associates data to operationinformation such that an advertisement group (data) related to the upperfloor is associated with operation information indicating that thisadvertisement group is displayed when the terminal 3920 is moved upward,while an advertisement group (data) related to the lower floor isassociated with operation information indicating that this advertisementgroup is displayed when the terminal 3920 is moved downward. Theterminal 3920 receives this modulated light signal and storesadvertisement groups related to the upper floor and the lower floorincluded in the received modulated light signal and also storesoperation information.

When a pedestrian (user) in a facility moves (for example, tilts orrotates) the terminal upward, the terminal 3920 displays, on a screen,the advertisement group related to the upper floor associated with theupward movement in the operation information. When a pedestrian (user)in the facility moves (for example, tilts or rotates) the terminal 3920downward, the terminal 3920 may display, on the screen, theadvertisement group related to the lower floor associated with thedownward movement in the operation information operation.

When the terminal is rotated upward, the advertisement group related tothe upper floor may be displayed on the screen, while when the terminalis rotated downward, the advertisement group related to the lower floormay be displayed on the screen.

FIG. 43 is a diagram illustrating an example in which a plurality ofilluminations 3903 are arranged side by side.

In FIG. 43, a plurality of illuminations 3903 are prepared, and eachillumination 3903 is assigned an ID (identification). The terminal 3920detects IDs of two or more illuminations 3903 thereby recognizing adirection (a traveling direction) in which the terminal 3920 is moving.For example, when ID4 and ID6 are detected, it is determined that theterminal is moving in a rightward direction. Alternatively, from animage captured by an image sensor, the terminal 3920 may detect thedirection (traveling direction) in which the terminal itself is moving.

In FIG. 43, an ID is assigned to each of the plurality of illuminations3903. The communication apparatus 3900 transmits, from the illumination3903, data including the ID of the illumination 3903. When the terminal3920 receives data from the illumination 3903, the terminal 3920identifies the ID of the illumination 3903 that is the transmissionsource of the data.

The terminal 3920 estimates the movement direction of the terminal 3920based on the reception order of the IDs of the at least twoilluminations 3903. For example, in FIG. 43, when the terminal receivesIDs of illuminations 3903 in the order of ID4, ID5, and ID6, theterminal 3920 estimates that the terminal 3920 is moving in a directionfrom ID4 (left) to ID6 (right). Note that the terminal 3920 may capturelight from illuminations 3903 by an image sensor, and may recognize thetraveling direction of the terminal 3920 based on the image captured bythe image sensor.

In the present embodiment, the communication apparatus 3900 transmitsdata associated with operation information including information on themovement operation of terminal 3920 that causes the data to bedisplayed. On the terminal 3920, data associated with the movementoperation of the terminal 3920 is selected from a plurality of pieces ofdata and is displayed. Thus, the user can cause the terminal 3920 todisplay appropriate data only by moving (for example, tilting orrotating) the terminal 3920.

As a matter of course, a plurality of embodiments disclosed in thepresent description and/or other elements may be combined inimplementation. That is, the contents of the above-described embodimentsmay be arbitrarily combined. In Embodiments 8 to 10 described above, itis assumed by way of example that the communication apparatus 3900transmits data to terminals using a light wave (modulated light signal).However, instead of the light wave (modulated light signal), a radiowave may be used in transmission of data to terminals. The operations ofthe terminal disclosed in Embodiments 8 to 10 may be realized asoperations of an application program installed in the terminal.

In Embodiment 8 and following Embodiments, it is assumed by way ofexample that the communication apparatus 3900 is installed in a trainand a terminal communicates with this communication apparatus 3900.However, these embodiments may also be implemented in a case where acommunication apparatus is installed in a vehicle such as a bus, anaircraft, or the like and a terminal communicates with the communicationapparatus 3900. The communication apparatus 3900 may transmitinformation including time information in addition to locationinformation such that the terminal is allowed to obtain the locationinformation and the time information via communication with thecommunication apparatus 3900.

In Embodiment 8 and following Embodiments, instead of transmittinginformation using a modulated light signal, the information may betransmitted using a radio wave.

In FIG. 32, FIG. 36, FIG. 40, and FIG. 41, the communication apparatus3900 may include a not-shown interface for updating data in the dataselection unit 3901. That is, the data selection unit 3901 shown in FIG.32, FIG. 36, FIG. 40, FIG. 41 or elsewhere may communicate with anotherdevice or a server to update data.

Note that the embodiments are described only to illustrate examples. Forexample, “modulation schemes, error correction coding schemes (errorcorrection code used, code length, coding rate, etc.), controlinformation and/or the like” may be replaced by other “modulationschemes, error correction coding schemes (error correction code used,code length, coding rate, etc.), control information and/or the like.

It is assumed in the description by way of example that information isadvertisement information. However, the advertisement information may beinformation related to an application installed on a terminal andoperated thereon. The advertisement information may be information on aURL from which it is allowed to obtain an application to be installed onthe terminal and operated thereon.

In the above description, explanations are made by way of example forthe case where the communication apparatus transmits information relatedto an advertisement. Hereinafter, examples are described in whichinformation other than advertisements is transmitted.

In a situation in the communication apparatus 3900 is installed on atrain, the communication apparatus 3900 may transmit information relatedto a map of a platform of a station existing in the direction in whichthe train is traveling (for example, Shinagawa Station and otherstations beyond at which the train will stop, in a case where the trainis traveling to Shinagawa Station after leaving Shin-Yokohama Station).The information related to the map may be information indicating the mapitself, or information on a URL related to the map. Information on a mapof a platform may include information related to a ticket gate andinformation related to nearby facilities and buildings. In a case wherethe communication apparatus is installed on an airplane, thecommunication apparatus 3900 may transmit information on a map of anairport the airplane is approaching. The information related to the mapmay be information indicating the map itself, or information on a URLrelated to the map.

In a case where the communication apparatus 3900 is installed on a bus,the communication apparatus 3900 may transmit a modulated light signalinside the bus or may transmit outside the bus. In the case where themodulated light signal is transmitted to the outside of the bus, thetransmitted modulated light signal may include information on adestination of the bus and bus stops at which the bus will stop. In thiscase, the information may not include information on bus stops that thebus already left.

Similarly, in a case where the communication apparatus 3900 is installedon a train, the communication apparatus 3900 may transmit a modulatedlight signal inside the train or outside the train. In the case wherethe modulated light signal is transmitted to the outside of the train,the transmitted modulated light signal may include information on adestination of the train and stations at which the train will stop. Inthis case, the information may not include information on stations thatthe train already left.

When a terminal obtains information from the communication apparatus3900 and an image (a still image, a moving image) via an image sensor,the terminal may store them, for example, in a memory (storage unit)disposed on the terminal such that a user using the terminal is allowedto read the stored information as needed, which provides improvedconvenience to the user. In this case, the communication apparatus 3900does not necessarily need to be implemented in a vehicle such as atrain, a bus, an airplane, or the like.

Note that the information obtained from the communication apparatus 3900may be displayed on a display disposed on the terminal such that theinformation is superimposed on an image, or the information obtainedfrom the communication apparatus 3900 may be displayed separately(without overlapping) from the image.

When information, such as information about disasters, information aboutoperations, or the like, occurs that needs to be broadcast urgently, thecommunication apparatus 3900 may stop the distribution of informationrelated to advertisements, and may distribute the information itselfthat needs to be broadcast urgently, or information on a URL of a serverthat provides the information that needs to be broadcast urgently.Alternatively, without stopping the distribution of the informationrelated to the advertisements, the information itself that needs to beurgently distributed or the information on the URL of the server thatprovides the information that needs to be urgently distributed may bedistributed.

Embodiment 11

Embodiment 11 discloses a method of updating data of the data selectionunit 3901 in the communication apparatus 3900 shown in FIG. 32, FIG. 36,FIG. 40, FIG. 41, or elsewhere.

FIG. 44 illustrates an example of a manner of connecting apparatuses inthe data update method. The communication apparatus 3900 communicateswith a data generation apparatus 5100, which allows the data selectionunit 3901 disposed in the communication apparatus 3900 to acquire datagenerated by the data generation apparatus 5100 thereby updatinginformation such as an advertisement or the like to be delivered toterminals.

The data generation apparatus 5100 also communicates with an apparatus#k (5101_k) in addition to the communication apparatus 3900 where k isan integer in a range from 1 to N (inclusive). Herein H is an integergreater than or equal to 2. In this situation, the apparatus #k (5101_k)transmits, to the data generation apparatus 5100, information such as aspecific content of the advertisement, information on a place/sectionwhere the advertisement is delivered, a bid price, or the like.

FIG. 45 shows an example of a bid status of an advertisement generatedby the data generation apparatus 5100 in FIG. 44. For example, theapparatus #k (5101_k) in FIG. 44 obtains the information such as thatdescribed in FIG. 45, and displays the acquired information on a displayof the apparatus #k (5101_k) such that a user (who is a candidate of anadvertiser) of the apparatus #k (5101_k) can get to know theinformation.

FIG. 45 illustrates an example of a bid status of an advertisementtransmitted in a train running from Shin-Yokohama Station to ShinagawaStation and further to Tokyo Station in a section from Yokohama Stationto Shinagawa Station as shown in FIG. 33, 35, 37, or 39. In FIG. 45, ahorizontal axis represents places.

For example, in a region 5200 in FIG. 45, a request for distributing anadvertisement #A is offered from a certain apparatus (a certain user).In this region, it has not yet been decided to distribute theadvertisement #A, and thus another apparatus (user) is allowed tofurther bid on another advertisement. Note that the region 5200 is aregion for indicating information related to an advertisement to bedelivered in a section from Shin-Yokohama Station to a point #2. In thisregard, a description has already been given in other embodiments, andthus a further detailed explanation is omitted.

In a region 5201 in FIG. 45, a request for distributing an advertisement#D is offered from a certain apparatus (a certain user), and it hasalready been decided to distribute the advertisement #D. Note that theregion 5201 is a region for indicating information related to anadvertisement to be delivered in a section from a point #2 to ShinagawaStation. In this regard, a description has already been given in otherembodiments, and thus a further detailed explanation is omitted.

In a region 5202 in FIG. 45, a request for distributing an advertisement#B is offered from a certain apparatus (a certain user). In this region,it has not yet been decided to distribute the advertisement #B, and thusanother apparatus (user) is allowed to further bid on anotheradvertisement. Note that the region 5202 is a region for indicatinginformation related to an advertisement to be delivered in a sectionfrom Shin-Yokohama Station to a point #3. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 5203 in FIG. 45, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region5203 is a region for indicating information related to an advertisementto be delivered in a section from the point #3 to Shinagawa Station. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 5204 in FIG. 45, a request for distributing an advertisement#C is offered from a certain apparatus (a certain user). In this region,it has already been decided to distribute an advertisement #D, and thusa further bid on an advertisement by any apparatus (any user) is notallowed. Note that the region 5204 is a region for indicatinginformation related to an advertisement to be delivered in a sectionfrom Shin-Yokohama Station to the point #1. In this regard, adescription has already been given in other embodiments, and thus afurther detailed explanation is omitted.

In a region 5205 in FIG. 45, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region5205 is a region for indicating information related to an advertisementto be delivered in a section from the point #1 to Shinagawa Station. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 5206 in FIG. 45, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region5206 is a region for indicating information related to an advertisementto be delivered in a section from Shin-Yokohama Station to ShinagawaStation. In this regard, a description has already been given in otherembodiments, and thus a further detailed explanation is omitted.

In a region 5207 in FIG. 45, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region5207 is a region for indicating information related to an advertisementto be delivered in a section from Shin-Yokohama Station to ShinagawaStation. In this regard, a description has already been given in otherembodiments, and thus a further detailed explanation is omitted.

An apparatus #k (5101_k) in FIG. 44 acquires information on the statusshown in FIG. 45 from the data generation apparatus 5100. Taking intoconsideration the status, the apparatus #k (5101_k) offers a request foran advertisement distribution and bids on it. When placing the bid, theapparatus #k (5101_k) provides a content of the advertisement to thedata generation apparatus 5100.

In response, the data generation apparatus 5100 may have a function ofchecking appropriateness of the content of the advertisement provided bythe apparatus #k (5101_k). For example, in the case of FIG. 45, anadvertisement related to Shin-Yokohama Station and nearby locations andan advertisement related to an already passed station beforeShin-Yokohama Station are not suitable as advertisements. The datageneration apparatus 5100 may have a function of checking whether theadvertisement is such an advertisement. When the advertisement isdetermined to be an inappropriate advertisement, it will not be providedto the communication apparatus 3900.

In the data generation apparatus 5100 of FIG. 44, when bidding foradvertisements is completed, the data possessed by the data selectionunit 3901 of the communication apparatus 3900 is updated. For example,the data is updated as described below in “Example 7” or “Example 8”.

Example 7

When the data selection unit 3901 in the communication apparatus 3900has advertisements themselves, terminals obtain the updatedadvertisements based on the updated data.

Example 8

It is assumed that when the data selection unit 3901 of thecommunication apparatus 3900 acquires, for example, URL information of aserver providing an advertisement, the data generation apparatus 5100also has a function as a content server. In this case, the terminal isdirected to the data generation apparatus 5100 via the communicationwith the communication apparatus 3900, and receives an advertisementfrom the data generation apparatus 5100. Note that in a case where thedata generation apparatus 5100 does not have the function of the contentserver, and another server has and provides the content of theadvertisement, the terminal obtains the updated advertisement from thisserver.

The bid status of advertisements in FIG. 45 is merely an example. Forexample, bids on advertisements may be placed for other train sections.A bid for an advertisement may be made for each hour or time.

This point will be described below with reference to FIG. 46. FIG. 46shows an example of a bid status of advertisements generated by the datageneration apparatus 5100 shown in FIG. 44. For example, the apparatus#k (5101_k) in FIG. 44 obtains the information such as that described inFIG. 46, and displays the acquired information on a display of theapparatus #k (5101_k) such that a user (who is a candidate of anadvertiser) of the apparatus #k (5101_k) can get to know theinformation.

FIG. 46 illustrates an example of a bid status of an advertisementtransmitted in a train running from Shin-Yokohama Station to ShinagawaStation and further to Tokyo Station in a section from Yokohama Stationto Shinagawa Station as shown in FIG. 33, 35, 37, or 39. In FIG. 45, ahorizontal axis represents places, and a vertical axis represents time.

For example, in a region 5300 in FIG. 46, a request for distributing anadvertisement #A is offered from a certain apparatus (a certain user),and it has already been decided to distribute the advertisement #A. Notethat the region 5300 is a region for indicating information related toan advertisement to be delivered in a section from Shin-Yokohama Stationto the point #1 and in a time zone from 10 o'clock to 12 o'clock. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 5301 in FIG. 46, a request for distributing an advertisement#B is offered from a certain apparatus (a certain user). In this region,it has not yet been decided to distribute the advertisement #B, and thusanother apparatus (user) is allowed to further bid on anotheradvertisement. Note that the region 5301 is a region for indicatinginformation related to an advertisement to be delivered in a sectionfrom the point #1 to the point #3 and in a time zone from 10 o'clock to11 o'clock. In this regard, a description has already been given inother embodiments, and thus a further detailed explanation is omitted.

In a region 5302 in FIG. 46, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region5302 is a region for indicating information related to an advertisementto be delivered in a section from the point #3 to Shinagawa Station andin a time zone from 10 o'clock to 11 o'clock. In this regard, adescription has already been given in other embodiments, and thus afurther detailed explanation is omitted.

In a region 5303 in FIG. 46, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region5303 is a region for indicating information related to an advertisementto be delivered in a section from the point #1 to the point #2 and in atime zone from 11 o'clock to 12 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 5304 in FIG. 46, a request for distributing an advertisement#C is offered from a certain apparatus (a certain user), and it hasalready been decided to distribute the advertisement #C. Note that theregion 5304 is a region for indicating information related to anadvertisement to be delivered in the section from the point #2 toShinagawa Station and in the time zone from 11 o'clock to 12 o'clock. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

An apparatus #k (5101_k) in FIG. 44 acquires information on the statusshown in FIG. 46 from the data generation apparatus 5100. Taking intoconsideration the status, the apparatus #k (5101_k) offers a request foran advertisement distribution and bids on it. When placing the bid, theapparatus #k (5101_k) provides a content of the advertisement to thedata generation apparatus 5100.

In response, the data generation apparatus 5100 may have a function ofchecking appropriateness of the content of the advertisement provided bythe apparatus #k (5101_k). For example, in the case of FIG. 46, anadvertisement related to Shin-Yokohama Station and nearby locations andan advertisement related to an already passed station beforeShin-Yokohama Station are not suitable as advertisements. The datageneration apparatus 5100 may have a function of checking whether theadvertisement is such an advertisement. When the advertisement isdetermined to be an inappropriate advertisement, it will not be providedto the communication apparatus 3900.

In the data generation apparatus 5100 of FIG. 44, when bidding foradvertisements is completed, the data possessed by the data selectionunit 3901 of the communication apparatus 3900 is updated. Examples ofupdating have already been described in “Example 7” and “Example 8”.

Note that the status of bids on advertisements shown in FIG. 46 ismerely an example. For example, bids on advertisements may be placed forother train sections, or bids on advertisements for other train sectionsmay be placed. In FIG. 46, each area indicates information related to abid for one advertisement, bids may be made for a plurality ofadvertisements by a plurality of apparatuses (that is, a plurality ofadvertisements may be delivered in the region).

By generating advertisement data in the above-described manner, itbecomes possible for terminals to receive more valuable data.

In the present description, the “illumination” or the “light source” maybe a display that is emitting light to display an image, a moving image,an advertisement, and/or the like and a modulated light signal may beincluded in the light. That is, the “illumination” or the “light source”may have a function in addition to the function of emitting light. The“illumination” or the “light source” may include a plurality of“lightings” or “light sources”.

The transmission method used by the communication apparatus ingenerating a modulated light signal and emits light may be a methodother than the transmission method described in the present description.The modulated light signal may include information other thaninformation described in the present description.

Embodiment 12

Embodiment 12 discloses modifications of Embodiment 8, Embodiment 9,Embodiment 10, and Embodiment 11. In particular, the present embodimentdescribed below is related to an application of visible lightcommunication to a “pedestrian”, a “communication apparatus possessed bya pedestrian”, and a “communication apparatus installed on a car (or avehicle, or the like)”.

FIG. 47 illustrates an example of a state of “person having acommunication apparatus” and “monitor configured to display at least animage/moving image” according to the present embodiment. The “monitor”may include a speaker configured to output an audio signal (a sound).

In FIG. 47, it is assumed that the “west gate” of the station is locatedon the upper side of FIG. 47 while the “east gate” of the station islocated on the lower side of FIG. 47. It is assumed that a “person 4711having a communication apparatus” is moving in a direction indicated byan arrow 4711_1, that is, he/she is moving toward the west gate. It isalso assumed that a “person 4712 having a communication apparatus” ismoving in a direction indicated by an arrow 4712_1, that is, he/she ismoving toward the west gate. It is assumed that a monitor 4751 faces ina direction indicated by an arrow 4751_1 and displays an “image/movingimage”. Furthermore, the monitor 4751 may transmit a modulated lightsignal. Note that the modulated light signal may be emitted from ascreen of the monitor displaying the image/moving image, or the monitormay include a light emitting unit for transmitting the modulated lightsignal.

Similarly, it is assumed that a monitor 4752 faces in a directionindicated by an arrow 4752_1 and displays an “image/moving image”.Furthermore, the monitor 4752 may transmit a modulated light signal.Note that the modulated light signal may be emitted from a screen of themonitor displaying the image/moving image, or the monitor may include alight emitting unit for transmitting the modulated light signal.

In this situation, the monitors 4751 and 4752 are monitors to be viewedby the “person 4711 having the communication apparatus” and the “person4712 having the communication apparatus”, respectively. In this case,the “person 4711 having his/her own communication apparatus” and the“person 4712 having his/her own communication apparatus” are movingtoward the west gate, and thus it is desirable that information or anadvertisement displayed by these “monitors 4751 and 4752” is useful forthe persons.

Therefore, the “monitors 4751 and 4752” may display an image/movingimage of “useful information or an advertisement related to something inthe direction to the west gate. Furthermore, the “monitors 4751 and4752” may transmit modulated light signal including an image/movingimage of “useful information or an advertisement related to something inthe direction to the west gate. This makes it possible to provideeffective information to “persons (users) having a communicationapparatus”.

It is assumed that a “person 4721 having a communication apparatus” ismoving in a direction indicated by an arrow 4721_1, that is, he/she ismoving toward the east gate. Similarly, it is assumed that a “person4722 having a communication apparatus” is moving in a directionindicated by an arrow 4722_1, that is, he/she is moving toward the eastgate.

It is assumed that a monitor 4761 faces in a direction indicated by anarrow 4761_1 and displays an “image/moving image”. Furthermore, themonitor 4761 may transmit a modulated light signal. Note that themodulated light signal may be emitted from a screen of the monitordisplaying the image/moving image, or the monitor may include a lightemitting unit for transmitting the modulated light signal.

Similarly, it is assumed that a monitor 4762 faces in a directionindicated by an arrow 4762_1 and displays an “image/moving image”.Furthermore, the monitor 4762 may transmit a modulated light signal.Note that the modulated light signal may be emitted from a screen of themonitor displaying the image/moving image, or the monitor may include alight emitting unit for transmitting the modulated light signal.

In this situation, the monitors 4761 and 4762 are monitors to be viewedby the “person 4721 having the communication apparatus” and the “person4722 having the communication apparatus”, respectively. In this case,the “person 4721 having the communication apparatus” and the “person4722 having the communication apparatus” are moving toward the eastgate, and thus it is desirable that information or an advertisementdisplayed by these “monitors 4761 and 4762” is useful for these persons.

Therefore, the “monitors 4761 and 4762” may display an image/movingimage of “useful information or an advertisement related to something inthe direction to the east gate. Furthermore, the “monitors 4761 and4762” may transmit modulated light signal including an image/movingimage of “useful information or an advertisement related to something inthe direction to the east gate. This makes it possible to provideeffective information to “persons (users) having a communicationapparatus”.

As described above, by providing information by monitors such that theprovided information is different depending on the moving direction, itis possible to provide information useful for users.

A “moving walkway” 4701 capable of moving in a direction indicated by anarrow 4711_1 or 47121 may be provided. A “moving walkway” 4702 capableof moving in a direction indicated by an arrow 4721_1 or 4722_1 may beprovided. Also, in this case, useful information may be provided to a“person (user) having a communication apparatus.

In FIG. 47, the directivity of the light of the modulated light signalemitted by each of the “monitors 4751 and 4752” is opposite to thedirectivity of the light of the modulated light signal emitted by eachof the “monitors 4761 and 4762”. This results in a reduction in apossibility that interfering light rays are received by a receptionapparatus that receives a modulated light signal, which results in animprovement in data reception quality.

FIG. 48 illustrates an example, different from the example in FIG. 47,of a state of “person having a communication apparatus” and “monitorconfigured to display at least an image/moving image” according to thepresent embodiment. The “monitor” may include a speaker configured tooutput an audio signal (a sound). In the following description, it isassumed that the “monitor” includes a speaker configured to output anaudio signal (a sound), and elements similar in operation to those shownin FIG. 47 are denoted by similar reference numerals.

In FIG. 48, it is assumed that the “west gate” of the station is locatedon the upper side of FIG. 48 while the “east gate” of the station islocated on the lower side of FIG. 48. It is assumed that a “person 4711having a communication apparatus” is moving in a direction indicated byan arrow 4711_1, that is, he/she is moving toward the west gate. It isalso assumed that a “person 4712 having a communication apparatus” ismoving in a direction indicated by an arrow 4712_1, that is, he/she ismoving toward the west gate.

It is assumed that a monitor 4751 faces in a direction indicated by anarrow 4751_1 and displays an “image/moving image”. Furthermore, themonitor 4751 may transmit a modulated light signal. Note that themodulated light signal may be emitted from a screen of the monitordisplaying the image/moving image, or the monitor may include a lightemitting unit for transmitting the modulated light signal.

Similarly, it is assumed that a monitor 4752 faces in a directionindicated by an arrow 4752_1 and displays an “image/moving image”.Furthermore, the monitor 4752 may transmit a modulated light signal.Note that the modulated light signal may be emitted from a screen of themonitor displaying the image/moving image, or the monitor may include alight emitting unit for transmitting the modulated light signal.

In this situation, the monitors 4751 and 4752 are monitors to be viewedby the “person 4711 having the communication apparatus” and the “person4712 having the communication apparatus”, respectively. In this case,the “person 4711 having the communication apparatus” and the “person4712 having the communication apparatus” are moving toward the westgate, and thus it is desirable that information or an advertisementdisplayed by these “monitors 4751 and 4752” is useful for the persons.

Therefore, the “monitors 4751 and 4752” may display an image/movingimage of “useful information or an advertisement related to something inthe direction to the west gate. Furthermore, the “monitors 4751 and4752” may transmit modulated light signal including an image/movingimage of “useful information or an advertisement related to something inthe direction to the west gate. This makes it possible to provideeffective information to “persons (users) having a communicationapparatus”.

It is assumed that a “person 4721 having a communication apparatus” ismoving in a direction indicated by an arrow 4721_1, that is, he/she ismoving toward the east gate.

Similarly, it is assumed that a “person 4722 having a communicationapparatus” is moving in a direction indicated by an arrow 4722_1, thatis, he/she is moving toward the east gate.

It is assumed that a monitor 4761 faces in a direction indicated by anarrow 4761_1 and displays an “image/moving image”. Furthermore, themonitor 4761 may transmit a modulated light signal. Note that themodulated light signal may be emitted from a screen of the monitordisplaying the image/moving image, or the monitor may include a lightemitting unit for transmitting the modulated light signal.

Similarly, it is assumed that a monitor 4762 faces in a directionindicated by an arrow 4762_1 and displays an “image/moving image”.Furthermore, the monitor 4762 may transmit a modulated light signal.Note that the modulated light signal may be emitted from a screen of themonitor displaying the image/moving image, or the monitor may include alight emitting unit for transmitting the modulated light signal.

In this situation, the monitors 4761 and 4762 are monitors to be viewedby the “person 4721 having the communication apparatus” and the “person4722 having the communication apparatus”, respectively. In this case,the “person 4721 having the communication apparatus” and the “person4722 having the communication apparatus” are moving toward the eastgate, and thus it is desirable that information or an advertisementdisplayed by these “monitors 4761 and 4762” is useful for these persons.

Therefore, the “monitors 4761 and 4762” may display an image/movingimage of “useful information or an advertisement related to something inthe direction to the east gate. Furthermore, the “monitors 4761 and4762” may transmit modulated light signal including an image/movingimage of “useful information or an advertisement related to something inthe direction to the east gate.

This makes it possible to provide effective information to “persons(users) having a communication apparatus”.

As described above, by providing information by monitors such that theprovided information is different depending on the moving direction, itis possible to provide useful information useful.

A “moving walkway” 4701 capable of moving in a direction indicated by anarrow 4711_1 or 47121 may be provided. A “moving walkway” 4702 capableof moving in a direction indicated by an arrow 4721_1 or 4722_1 may beprovided. This has a feature that a monitor that provides a movingimage/image related to information/advertisement and/or information islocated adjacent to the moving walkway. This provides a more appropriatemanner of providing effective information to “persons (users) having acommunication apparatus”.

In FIG. 48, the directivity of the light of the modulated light signalemitted by each of the “monitors 4751 and 4752” is opposite to thedirectivity of the light of the modulated light signal emitted by eachof the “monitors 4761 and 4762”. This results in a reduction in apossibility that interfering light rays are received by a receptionapparatus that receives a modulated light signal, which results in animprovement in data reception quality.

Present embodiment has been described above using names “west gate” and“east gate”. But the terms “west gate” and “east gate” are merelyexamples, but the terms are not limited to these examples. Theembodiment may be similarly implemented also for a case where two ormore different areas are respectively denoted as, for example, “area A”and “area B” instead of “west gate” and “east gate”. In another exampleof an implementation of the embodiment, a plurality of areas including“area #1, area #2, . . . area #N (where N is an integer greater than orequal to 2)” may be treated instead of “west gate”, and a plurality ofareas including “area $1, area $2, . . . area $M (where M is an integergreater than or equal to 2)” may be treated instead of “east gate”, Thisholds in Embodiment 10 and other Embodiments.

Note that the “monitors 4751 and 4752” in FIGS. 47 and 48 may treatinformation related to the east gate and an advertisement expressed inan image or a moving image. Similarly, the “monitors 4761 and 4762” inFIGS. 47 and 48 may treat information related to the west gate and anadvertisement expressed in an image or a moving image.

Furthermore, alternative examples of methods may be possible. Forexample, let it be assumed by way of example that another railwaystation exists at the east gate. In this case, information and/or anadvertisement related to an east gate area such as information and/or anadvertisement related to a railway destination area may be treatedaccording to the present embodiment.

In FIG. 47 and FIG. 48, in an alternative implementation of the presentembodiment, “persons 4711, 4712, 4721, and 4722 having a communicationapparatus” may be replaced by “vehicles equipped with a communicationapparatus”, or “car equipped with a communication apparatus”.

Embodiment 13

Embodiment 13 discloses a method of updating data of the data selectionunit 3901 in the communication apparatus 3900 shown in FIG. 49.

FIG. 49 shows an example of a configuration, different from that shownin FIG. 36, of a communication system. In FIG. 49, elements similar inoperation to those shown in FIG. 36 are denoted by similar referencenumerals. As for elements which have been already described above, afurther description thereof is omitted. The communication system shownin FIG. 49 is a communication system for implementing Embodiment 12.

The communication apparatus 3900 in FIG. 49 corresponds to the monitor4751, 4752, 4761, or 4762 in FIG. 47 or 48. Although only onecommunication apparatus 3900 is shown in FIG. 49, there may be aplurality of communication apparatuses.

In FIG. 49, a device including an apparatus 4900 including the“illumination 3903 and the display 4901 configured to display animage/moving image” may be used as a monitor, or an apparatus, such asthe communication apparatus 3900, including a modem in addition to theapparatus 4900 may be used.

FIG. 44 illustrates an example of a manner of connecting apparatuses inthe data update method. The communication apparatus 3900 communicateswith a data generation apparatus 5100, which allows the data selectionunit 3901 disposed in the communication apparatus 3900 to acquire datagenerated by the data generation apparatus 5100 thereby updatinginformation and/or an advertisement to be delivered to terminals via themodulated light signal and updating a content of information,advertisement, an image, and/or a moving images to be displayed on thedisplay 4901.

The data generation apparatus 5100 also communicates with an apparatus#k (5101_k) in addition to the communication apparatus 3900 where k isan integer in a range from 1 to N (inclusive). Herein H is an integergreater than or equal to 2. (or H may be equal to 1). In this situation,the apparatus #k (5101_k) transmits, to the data generation apparatus5100, an advertisement (a still image, a moving image, audio signal) ora specific content of information, information related to aplace/section whether the content is to be delivered, informationindicating such as a specific content of the advertisement, informationon a place/section where the advertisement is delivered, a bid price, orthe like.

FIG. 50 illustrates an example of a bid status of an advertisementgenerated by the data generation apparatus 5100 shown in FIG. 44. Forexample, the apparatus #k (5101_k) in FIG. 44 obtains the informationsuch as that described in FIG. 50, and displays the acquired informationon a display of the apparatus #k (5101_k) such that a user (who is acandidate of an advertiser) of the apparatus #k (5101_k) can get to knowthe information.

FIG. 50 illustrates an example of a bid status of an advertisementtransmitted in the section from the east gate to the west gate as shownin FIG. 47 or 48. The bid status of the advertisement in FIG. 50 is abid status in terms of an advertisement to be displayed on a display(4901 in FIG. 49) such as “monitor 4751 or 4752” in FIG. 47 or 48. Notethat the “advertisement” may be information other than advertisements.

For example, in a region 50-00 in FIG. 50, a request for distributing an“advertisement #A for being displayed” on a monitor or the like in asection from the east gate to a point #2 is offered from a certainapparatus (a certain user). In this region, it has not yet been decidedto distribute the advertisement #A, and thus another apparatus (user) isallowed to further bid on another advertisement. Note that the region50-00 is a region for indicating information related to an advertisementto be delivered in the section from the east gate to the point #2. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 50-01 in FIG. 50, a request for distributing an“advertisement #D for being displayed” on a monitor or the like in thesection from the point #2 to the west gate is offered from a certainapparatus (a certain user), and it has already been decided todistribute the advertisement #D. Note that the region 50-01 is a regionfor indicating information related to an advertisement to be deliveredin the section from the point #2 to the west gate. In this regard, adescription has already been given in other embodiments, and thus afurther detailed explanation is omitted.

In a region 50-02 in FIG. 50, a request for distributing an“advertisement #B for being displayed” on a monitor or the like in asection from the east gate to a point #3 is offered from a certainapparatus (a certain user). In this region, it has not yet been decidedto distribute the advertisement #B, and thus another apparatus (user) isallowed to further bid on another advertisement. Note that the region50-02 is a region for indicating information related to an advertisementto be delivered in the section from the east gate to the point #3. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 50-03 in FIG. 50, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region50-03 is a region for indicating information related to an advertisementto be delivered in the section from the point #3 to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 50-04 in FIG. 50, a request for distributing an“advertisement #C for being displayed” on a monitor or the like in asection from the east gate to a point #1 is offered from a certainapparatus (a certain user). In this region, it has already been decidedto distribute an advertisement #C, and thus a further bid on anadvertisement by any apparatus (any user) is not allowed. Note that theregion 50-04 is a region for indicating information related to anadvertisement to be delivered in the section from the east gate to thepoint #1. In this regard, a description has already been given in otherembodiments, and thus a further detailed explanation is omitted.

In a region 50-05 in FIG. 50, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region50-05 is a region for indicating information related to an advertisementto be delivered in the section from the point #1 to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 50-06 in FIG. 50, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region50-06 is a region for indicating information related to an advertisementto be delivered in the section from the east gate to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 50-07 in FIG. 50, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region50-07 is a region for indicating information related to an advertisementto be delivered in a section from the east gate to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

An apparatus #k (5101_k) in FIG. 44 acquires information on the statusshown in FIG. 50 from the data generation apparatus 5100. Taking intoconsideration the status, the apparatus #k (5101_k) offers a request foran advertisement distribution and bids on it. When placing the bid, theapparatus #k (5101_k) provides a content of the advertisement to thedata generation apparatus 5100.

In response, the data generation apparatus 5100 may have a function ofchecking appropriateness of the content of the advertisement provided bythe apparatus #k (5101_k). For example, in the case of FIG. 50,advertisements related to the east gate and nearby locations are notsuitable as advertisements. The data generation apparatus 5100 may havea function of checking whether the advertisement is such anadvertisement. When the advertisement is determined to be aninappropriate advertisement, it will not be provided to thecommunication apparatus 3900.

In the data generation apparatus 5100 of FIG. 44, when bidding foradvertisements is completed, the data possessed by the data selectionunit 3901 of the communication apparatus 3900 is updated. The bid statusof advertisements in FIG. 50 is merely an example. A bid for anadvertisement may be made for each time zone or time.

This point will be described below with reference to FIG. 51. FIG. 51shows an example of a bid status of advertisements generated by the datageneration apparatus 5100 shown in FIG. 44. For example, the apparatus#k (5101_k) in FIG. 44 obtains the information such as that described inFIG. 51, and displays the acquired information on a display of theapparatus #k (5101_k) such that a user (who is a candidate of anadvertiser) of the apparatus #k (5101_k) can get to know theinformation.

FIG. 51 illustrates an example of a bid status of an advertisementtransmitted in the section from the east gate to the west gate as shownin FIG. 47 or 48. In FIG. 51, a horizontal axis represents places. Thebid status of the advertisement in FIG. 51 is a bid status in terms ofan advertisement to be displayed on a display (4901 in FIG. 49) such as“monitor 4751 or 4752” in FIG. 47 or 48. Note that the “advertisement”may be information other than advertisements.

For example, in a region 51-00 in FIG. 51, a request for distributing an“advertisement #A for being displaying” on a monitor or the like in thesection from the east gate to the point #1 is offered from a certainapparatus (a certain user), and it has already been decided todistribute the advertisement #A. Note that the region 51-00 is a regionfor indicating information related to an advertisement to be deliveredin the section from the east gate to the point #1 and in a time zonefrom 10 o'clock to 12 o'clock. In this regard, a description has alreadybeen given in other embodiments, and thus a further detailed explanationis omitted.

In a region 51-01 in FIG. 51, a request for distributing an“advertisement #B for being displayed” on a monitor or the like in thesection from the point #1 to the point #3 is offered from a certainapparatus (a certain user). In this region, it has not yet been decidedto distribute the advertisement #B, and thus another apparatus (user) isallowed to further bid on another advertisement. Note that the region51-01 is a region for indicating information related to an advertisementto be delivered in the section from the point #1 to the point #3 in atime zone from 10 o'clock to 11 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 51-02 in FIG. 51, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region51-02 is a region for indicating information related to an advertisementto be delivered in a section from the point #3 to the west gate and in atime zone from 10 o'clock to 11 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 51-03 in FIG. 51, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region51-03 is a region for indicating information related to an advertisementto be delivered in a section from the point #1 to the point #2 and in atime zone from 11 o'clock to 12 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 51-04 in FIG. 51, a request for distributing an“advertisement #C for being displayed” on a monitor or the like in thesection from the point #2 to the west gate is offered from a certainapparatus (a certain user), and it has already been decided todistribute the advertisement #C. Note that the region 51-04 is a regionfor indicating information related to an advertisement to be deliveredin the section from the point #2 to the west gate and in the time zonefrom 11 o'clock to 12 o'clock. In this regard, a description has alreadybeen given in other embodiments, and thus a further detailed explanationis omitted.

An apparatus #k (5101_k) in FIG. 44 acquires information on the statusshown in FIG. 51 from the data generation apparatus 5100. Taking intoconsideration the status, the apparatus #k (5101_k) offers a request foran advertisement distribution and bids on it. When placing the bid, theapparatus #k (5101_k) provides a content of the advertisement to thedata generation apparatus 5100.

In response, the data generation apparatus 5100 may have a function ofchecking appropriateness of the content of the advertisement provided bythe apparatus #k (5101_k). For example, in the case of FIG. 51,advertisements related to the east gate and nearby locations are notsuitable as advertisements. The data generation apparatus 5100 may havea function of checking whether the advertisement is such anadvertisement. When the advertisement is determined to be aninappropriate advertisement, it will not be provided to thecommunication apparatus 3900.

In the data generation apparatus 5100 of FIG. 44, when bidding foradvertisements is completed, the data possessed by the data selectionunit 3901 of the communication apparatus 3900 is updated.

The bid status of advertisements in FIG. 51 is merely an example. InFIG. 51, each area indicates information related to a bid for oneadvertisement, bids may be made for a plurality of advertisements by aplurality of apparatuses (that is, a plurality of advertisements may bedelivered in the region).

FIG. 52 illustrates a further another example of a bid status of anadvertisement generated by the data generation apparatus 5100 shown inFIG. 44. For example, the apparatus #k (5101_k) in FIG. 44 obtains theinformation such as that described in FIG. 52, and displays the acquiredinformation on a display of the apparatus #k (5101_k) such that a user(who is a candidate of an advertiser) of the apparatus #k (5101_k) canget to know the information.

FIG. 52 illustrates an example of a bid status of an advertisementtransmitted in a section from the east gate to the west gate as shown inFIG. 47 or 48. In FIG. 52, a horizontal axis represents places. The bidstatus of the advertisement in FIG. 52 is a bid status in terms of anadvertisement included in a modulated light signal to be transmitted(emitted), for example, by an illumination (3903 in FIG. 49) of such as“monitor 4751 or 4752” in FIG. 47 or 48. Note that the “advertisement”may be information other than advertisements.

For example, in a region 52-00 in FIG. 52, a request for distributing an“advertisement #a for being transmitted” to a monitor or the like in asection from the east gate to a point #2 is offered from a certainapparatus (a certain user). In this region, it has not yet been decidedto distribute the advertisement #a, and thus another apparatus (user) isallowed to further bid on another advertisement. Note that the region52-00 is a region for indicating information related to an advertisementto be delivered in a section from the east gate to the point #2. In thisregard, a description has already been given in other embodiments, andthus a further detailed explanation is omitted.

In a region 52-01 in FIG. 52, a request for distributing an“advertisement #d for being transmitted” to a monitor or the like in asection from the point #2 to the west gate is offered from a certainapparatus (a certain user), and it has already been decided todistribute the advertisement #d. Note that the region 52-01 is a regionfor indicating information related to an advertisement to be deliveredin the section from the point #2 to the west gate. In this regard, adescription has already been given in other embodiments, and thus afurther detailed explanation is omitted.

In a region 52-02 in FIG. 52, a request for distributing an“advertisement #b for being transmitted” to a monitor or the like in asection from the east gate to a point #3 is offered from a certainapparatus (a certain user). In this region, it has not yet been decidedto distribute the advertisement #b, and thus another apparatus (user) isallowed to further bid on another advertisement. Note that the region52-02 is a region for indicating information related to an advertisementto be delivered in the section from the east gate to the point #3. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 52-03 in FIG. 52, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region52-03 is a region for indicating information related to an advertisementto be delivered in the section from the point #3 to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 52-04 in FIG. 52, a request for distributing an“advertisement #c for being transmitted” to a monitor or the like in asection from the east gate to a point #1 is offered from a certainapparatus (a certain user). In this region, it has already been decidedto distribute an advertisement #c, and thus a further bid on anadvertisement by any apparatus (any user) is not allowed. Note that theregion 52-04 is a region for indicating information related to anadvertisement to be delivered in the section from the east gate to thepoint #1. In this regard, a description has already been given in otherembodiments, and thus a further detailed explanation is omitted.

In a region 52-05 in FIG. 52, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region52-05 is a region for indicating information related to an advertisementto be delivered in the section from the point #1 to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 52-06 in FIG. 52, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region52-06 is a region for indicating information related to an advertisementto be delivered in the section from the east gate to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

In a region 52-07 in FIG. 52, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region52-07 is a region for indicating information related to an advertisementto be delivered in the section from the east gate to the west gate. Inthis regard, a description has already been given in other embodiments,and thus a further detailed explanation is omitted.

An apparatus #k (5101_k) in FIG. 44 acquires information on the statusshown in FIG. 52 from the data generation apparatus 5100. Taking intoconsideration the status, the apparatus #k (5101_k) offers a request foran advertisement distribution and bids on it. When placing the bid, theapparatus #k (5101_k) provides a content of the advertisement to thedata generation apparatus 5100.

In response, the data generation apparatus 5100 may have a function ofchecking appropriateness of the content of the advertisement provided bythe apparatus #k (5101_k). For example, in the case of FIG. 52,advertisements related to the east gate and nearby locations are notsuitable as advertisements. The data generation apparatus 5100 may havea function of checking whether the advertisement is such anadvertisement. When the advertisement is determined to be aninappropriate advertisement, it will not be provided to thecommunication apparatus 3900.

In the data generation apparatus 5100 of FIG. 44, when bidding foradvertisements is completed, the data possessed by the data selectionunit 3901 of the communication apparatus 3900 is updated.

The bid status of advertisements in FIG. 52 is merely an example. A bidfor an advertisement may be made for each hour or time.

This point will be described below with reference to FIG. 53. FIG. 53shows an example of a bid status of advertisements generated by the datageneration apparatus 5100 shown in FIG. 44. For example, the apparatus#k (5101_k) in FIG. 44 obtains the information such as that described inFIG. 53, and displays the acquired information on a display of theapparatus #k (5101_k) such that a user (who is a candidate of anadvertiser) of the apparatus #k (5101_k) can get to know theinformation.

FIG. 53 illustrates an example of a bid status of an advertisementtransmitted in the section from the east gate to the west gate as shownin FIG. 47 or 48. In FIG. 53, a horizontal axis represents places. Thebid status of the advertisement in FIG. 53 is a bid status in terms ofan advertisement included in a modulated light signal to be transmitted(emitted), for example, by an illumination (3903 in FIG. 49) of such as“monitor 4751 or 4752” in FIG. 47 or 48. Note that the “advertisement”may be information other than advertisements.

For example, in a region 53-00 in FIG. 53, a request for distributing an“advertisement #a for being transmitted” to a monitor or the like in thesection from the east gate to the point #1 is offered from a certainapparatus (a certain user), and it has already been decided todistribute the advertisement #a. Note that the region 53-00 is a regionfor indicating information related to an advertisement to be deliveredin the section from the east gate to the point #1 and in a time zonefrom 10 o'clock to 12 o'clock. In this regard, a description has alreadybeen given in other embodiments, and thus a further detailed explanationis omitted.

In a region 53-01 in FIG. 53, a request for distributing an“advertisement #b for being transmitted” to a monitor or the like in thesection from the point #1 to the point #3 is offered from a certainapparatus (a certain user). In this region, it has not yet been decidedto distribute the advertisement #b, and thus another apparatus (user) isallowed to further bid on another advertisement. Note that the region53-01 is a region for indicating information related to an advertisementto be delivered in the section from the point #1 to the point #3 in atime zone from 10 o'clock to 11 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 53-02 in FIG. 53, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region53-02 is a region for indicating information related to an advertisementto be delivered in the section from the point #3 to the west gate and ina time zone from 10 o'clock to 11 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 53-03 in FIG. 53, no request for distributing anadvertisement is offered from any apparatus (any user), and thus it isallowed to bid on an advertisement distribution. Note that the region53-03 is a region for indicating information related to an advertisementto be delivered in a section from the point #1 to the point #2 and in atime zone from 11 o'clock to 12 o'clock. In this regard, a descriptionhas already been given in other embodiments, and thus a further detailedexplanation is omitted.

In a region 53-04 in FIG. 53, a request for distributing an“advertisement #c for being transmitted” to a monitor or the like in thesection from the point #2 to the west gate is offered from a certainapparatus (a certain user), and it has already been decided todistribute the advertisement #c. Note that the region 53-04 is a regionfor indicating information related to an advertisement to be deliveredin the section from the point #2 to the west gate and in the time zonefrom 11 o'clock to 12 o'clock. In this regard, a description has alreadybeen given in other embodiments, and thus a further detailed explanationis omitted.

An apparatus #k (5101_k) in FIG. 44 acquires information on the statusshown in FIG. 53 from the data generation apparatus 5100. Taking intoconsideration the status, the apparatus #k (5101_k) offers a request foran advertisement distribution and bids on it. When placing the bid, theapparatus #k (5101_k) provides a content of the advertisement to thedata generation apparatus 5100.

In response, the data generation apparatus 5100 may have a function ofchecking appropriateness of the content of the advertisement provided bythe apparatus #k (5101_k). For example, in the case of FIG. 53,advertisements related to the east gate and nearby locations are notsuitable as advertisements. The data generation apparatus 5100 may havea function of checking whether the advertisement is such anadvertisement. When the advertisement is determined to be aninappropriate advertisement, it will not be provided to thecommunication apparatus 3900.

In the data generation apparatus 5100 of FIG. 44, when bidding foradvertisements is completed, the data possessed by the data selectionunit 3901 of the communication apparatus 3900 is updated. The bid statusof advertisements in FIG. 53 is merely an example. In FIG. 53, each areaindicates information related to a bid for one advertisement, bids maybe made for a plurality of advertisements by a plurality of apparatuses(that is, a plurality of advertisements may be delivered in the region).

By generating advertisement data in the above-described manner, itbecomes possible for terminals and users to receive more valuable data,information, advertisements, images, an moving images. It also becomespossible for an information provider to provide more valuable data,information, advertisements, images, and moving images.

In the present description, the “illumination” or the “light source” maybe a display that is emitting light to display an image, a moving image,an advertisement, and/or the like and a modulated light signal may beincluded in the light. That is, the “illumination” or the “light source”may have a function in addition to the function of emitting light. The“illumination” or the “light source” may include a plurality of“lightings” or “light sources”.

The transmission method used by the communication apparatus ingenerating a modulated light signal and emits light may be a methodother than the transmission method described in the present description.The modulated light signal may include information other thaninformation described in the present description.

Present embodiment has been described above using names “west gate” and“east gate”. But the terms “west gate” and “east gate” are merelyexamples, but the terms are not limited to these examples. Theembodiment may be similarly implemented also for a case where two ormore different areas are respectively denoted as, for example, “area A”and “area B” instead of “west gate” and “east gate”. In another exampleof an implementation of the embodiment, a plurality of areas including“area #1, area #2, . . . area #N (where N is an integer greater than orequal to 2)” may be treated instead of “west gate”, and a plurality ofareas including “area $1, area $2, . . . area $M (where M is an integergreater than or equal to 2)” may be treated instead of “east gate”.

Note that the “monitors 4751 and 4752” in FIGS. 47 and 48 may treatinformation related to the east gate and an advertisement expressed inan image or a moving image. Similarly, the “monitors 4761 and 4762” inFIGS. 47 and 48 may treat information related to the west gate and anadvertisement expressed in an image or a moving image.

Furthermore, alternative examples of methods may be possible. Forexample, let it be assumed by way of example that another railwaystation exists at the east gate. In this case, information and/or anadvertisement related to an east gate area such as information and/or anadvertisement related to a railway destination area may be treatedaccording to the present embodiment.

In FIG. 47 and FIG. 48, in an alternative implementation of the presentembodiment, “persons 4711, 4712, 4721, and 4722 having a communicationapparatus” may be replaced by “vehicles equipped with a communicationapparatus”, or “car equipped with a communication apparatus”.

Embodiment 14

Embodiment 14 provides an example of a configuration of the datageneration apparatus 5100 in FIG. 44 described above in otherembodiments.

FIG. 54 illustrates an example of a configuration of the data generationapparatus 5100 shown in FIG. 44. The data generation apparatus 5100includes an API (Application Programming Interface) for performingprocessing. More specifically, for example, as shown in FIG. 54, thedata generation apparatus 5100 includes, as APIs, a recognition layerAPI 54-01_1, analysis layer API 54-01_2, a learning layer API 54-01_3, acommunication network layer API 54-01_4, and/or the like, which areconnected with an application connection API 54-02. Each API obtainsinformation, performs processing, and outputs processed data.

The application connection API 54-02 has an input/output signal 54-03.It is possible to change an API processing method and a processingalgorithm by the input/output signal 54-03. It is also possible tocontrol the order of processing performed by the APIs.

A first communication unit 54-04 is a communication unit forcommunicating with the apparatus #k (5101_k) shown in FIG. 44 where k isan integer in a range from 1 to H (inclusive). The first communicationunit 54-04 transfers information, such as information on a bid, obtainedfrom the apparatus #k (5101_k) to the application connection API 54-02.

The application connection API 54-02 transfers the information, such asinformation on a bid, obtained from the apparatus #k (5101_k) to eachAPI. On the other hand, the application connection API 54-02 transfers aresult obtained from each API to a distribution informationdetermination unit 54-06.

The distribution information determination unit 54-06 holds informationon a bid status such as that shown in FIG. 45, FIG. 46, FIG. 50, FIG.51, FIG. 52, FIG. 53, or FIG. 54.

The distribution information determination unit 54-06 transfers theinformation on the bid status to an API to which the information is tobe transferred, and obtains a result of processing performed by the API.The distribution information determination unit 54-06 then determines afinal content of the advertisement to be delivered.

The distribution information determination unit 54-06 transmits theinformation on the determined advertisement distribution content to thecommunication apparatus 3900 shown in FIG. 44 via a second communicationunit 54-05. Furthermore, based on the information on the determinedadvertisement distribution, the first communication unit 54-04 feedsback a bidding result to the apparatus #k (5101_k).

By performing the operation as described above, it is possible toachieve the effects described above in the respective embodiments. Notethat the configuration of the data generation apparatus 5100 is notlimited to that shown in FIG. 54. As a matter of course, a plurality ofembodiments disclosed in the present description and/or other technicalfeatures disclosed in supplements or the like may be combined inimplementation.

Also note that in each embodiment, the place where information such asan advertisement, an image, or a moving image may be an inside of anairplane or an aircraft. Also, in such a situation, any embodimentdescribed above may be implemented. Also, in this case, the effectsdescribed in the embodiment can be achieved.

Note that the embodiments are described only to illustrate examples. Forexample, “modulation schemes, error correction coding schemes (errorcorrection code used, code length, coding rate, etc.), controlinformation and/or the like” may be replaced by other “modulationschemes, error correction coding schemes (error correction code used,code length, coding rate, etc.), control information and/or the like.

As for the modulation scheme, a modulation scheme other than thosedescribed above in the present description may be employed inimplementations of the embodiments and other features. As for themodulation scheme, a modulation scheme other than those described abovein the present description may be employed in implementations of theembodiments and other features. For example, APSK (Amplitude Phase ShiftKeying) (for example, 16APSK, 64APSK, 128APSK, 256APSK, 1024APSK,4096APSK, etc.), PAM (Pulse Amplitude Modulation) (for example, 4PAM,8PAM, 16PAM, 64PAM, 128PAM, 256PAM, 256PAM, 1024PAM, 4096PAM etc.), PSK(Phase Shift Keying) (for example, BPSK, QPSK, 8PSK, 16PSK, 64PSK,128PSK, 256PSK, 1024PSK, 4096PSK etc.), QAM (Quadrature AmplitudeModulation) (for example, 4QAM, 8QAM, 16QAM, 64QAM, 128QAM, 256QAM,1024QAM, 4096QAM, etc.) may be employed, and uniform mapping ornon-uniform mapping may be employed in each modulation scheme. Schemesof signal constellation of 2, 4, 8, 16, 16, 64, 128, 256, 1024, etc.signal points in an IQ plane (in modulation schemes respectively having2, 4, 8, 16, 16, 64, 128, 256, 1024, etc. signal points) are not limitedto those of the modulation schemes shown in this specification.

The wireless apparatus described in this specification may be installed,in, for example, a communication/broadcasting device such as abroadcasting station, a base station, an access point, a terminal, amobile phone, or a communication device such as a television set, aradio set, a terminal, a personal computer, a mobile phones, an accesspoint, a base station, or the like. The wireless apparatus described inthis specification may be a device having a communication function andcapable of being connected via some interface with an apparatus such asa television set, a radio set, a personal computer, a mobile phone, orthe like, configured to execute an application.

The receiver disclosed in the present specification may be installed in,for example, a communication/broadcasting device such as a broadcastingstation, a base station, an access point, a terminal, a mobile phone, ora communication device such as a television set, a radio set, aterminal, a personal computer, a mobile phone, an access point, a basestation, or the like.

In wireless communication using a radio wave according to the presentembodiment, symbols other than data symbols, for example, pilot symbols(a preamble, a unique word, a postamble, a reference symbol, etc.),symbols for control information, etc. may be mapped in a frame in anarbitrary manner. Although naming such as pilot symbols, symbols forcontrol information, or the like is employed, any naming may be used,but the role of each symbol itself is important.

The pilot symbol may be, for example a known symbol PSK-modulated at atransmission/reception apparatus (or a reception apparatus may performsynchronization to get to know a symbol transmitted by a transmissionapparatus). Using this symbol, the reception apparatus performsfrequency synchronization, time synchronization, channel stateestimation (estimation of CSI (Channel State Information) (for eachmodulated signal), signal detection, and/or the like. Using this symbol,the receiver performs frequency synchronization, time synchronization,channel state estimation (estimation of CSI (Channel State Information)(for each modulated signal), signal detection, and/or the like.

The symbol for control information is a symbol for transmittinginformation (for example, information indicating a modulation scheme, anerror correction coding scheme used in communication, a coding rate ofthe error correction coding scheme, upper-layer setting information,and/or the like) that needs to be transmitted to a communication partnerto achieve transmission information other than data.

Note that the present disclosure is not limited to the embodimentsdescribed above, but many modifications or changes are possible. Forexample, although the above embodiments are implemented, by way ofexample, as a communication apparatus, the implementation is not limitedto the communication apparatus. The communication method may be realizedby software, hardware, or software in cooperation with hardware.

For example, a program for executing the communication method may bestored in advance in a ROM (Read Only Memory), and the program may beexecuted by a CPU (Central Processor Unit).

Furthermore, a program for executing the above communication method maybe stored in a computer-readable storage medium, and the program storedin the storage medium may be loaded in a RAM (Random Access Memory) ofthe computer and the computer may be operated according to the program.

Each functional block used in the description of each embodimentdescribed above can be partly or entirely realized by an LSI (LargeScale Integration) which is one type of integrated circuits, and eachprocess described in each embodiment may be partially or totallycontrolled by one LSI or a combination of LSIs. One LSI may be realizedby one chip. One chip may include part or all of functional blocks. EachLSI may include a data input and a data output. The LSI may also becalled an IC (Integrated Circuit), a system LSI, a super LSI, or anultra LSI depending on the integration density. The method ofimplementing the integrated circuit is not limited to the LSI, but theintegrated circuit may be implemented in the form of a dedicated circuitor a general-purpose processor. The integrated circuit may also berealized using an FPGA (Field Programmable Gate Array) that can beprogrammed after the LSI is produced or a reconfigurable processor thatis allowed to be reconfigured in terms of the connection or the settingof circuit cells in the inside of the LSI. The present disclosure may beimplemented by digital or analog processing. As a matter of course, if aprogress of a semiconductor technology or another technology derivedtherefrom provides a new technology for realizing an integrated circuitwhich can replace the LSI, functional blocks may be integrated using thenew technology. Use of biotechnology is potentially possible.

Note that at least one of the FPGA (Field Programmable Gate Array) andthe CPU (Centre Processing Unit) may be configured to be capable ofdownloading all or part of software for realizing the communicationmethod according to the present disclosure via wireless communication orwired communication. Furthermore, all or part of software for updatingmay be downloaded via wireless communication or wired communication. Thedownloaded software may be stored in a storage unit and at least one ofthe FPGA and the CPU may be operated according to the stored softwarethereby executing the digital signal processing according to the presentdisclosure.

In this case, a device including at least one of the FPGA and the CPUmay be connected to a communication modem wirelessly or by wire, and thecommunication method according to the present disclosure may be realizedby the device and the communication modem.

For example, a communication apparatus such as a base station, an AP, ora terminal described in the present description may include at least oneof the FPGA and the CPU, and the communication apparatus may include aninterface for acquiring, from the outside, software for operating atleast one of the FPGA and the CPU. The communication apparatus mayfurther include a storage unit for storing software acquired from theoutside, and the FPGA and/or the CPU may be operated based on the storedsoftware thereby realizing the signal processing described in thepresent disclosure.

INDUSTRIAL APPLICABILITY

An aspect of the present disclosure is useful for a visible lightcommunication system.

REFERENCE SIGNS LIST

-   -   100, 400, 1000, 1400A, 1400B device    -   102, 1404-1, 1404-2 transmitter    -   104, 1406-1, 1406-2 light source    -   150, 450, 1050 terminal    -   151 light receiver    -   153 receiver    -   155 data analysis unit    -   157 display    -   453, 2002 wireless apparatus    -   470, 2000 base station    -   2001 transmission apparatus    -   3900 communication apparatus    -   3901 data selection unit    -   3902 transmitter    -   3903 illumination    -   3920 terminal    -   5100 data generation apparatus

1. A communication apparatus installed in a vehicle, the communicationapparatus comprising: data selection circuitry which, in operation,acquires location and traveling direction information of the vehicle inmotion, selects, based on the location and traveling directioninformation, one advertisement candidate related to a location ahead ofa current location of the vehicle in motion, wherein the oneadvertisement candidate is selected from a plurality of advertisementcandidates for each of time and location resources defined by a timeaxis and a location zone, and acquires advertisement data correspondingto the selected one advertisement candidate for each of the time andlocation resources, wherein the advertisement data is differentdepending on the time and location resource; and transmission circuitrywhich, in operation, transmits a modulated light signal that includesthe acquired advertisement data, the modulated light signal being foruse by each of a plurality of mobile devices within the vehicle todisplay advertisement during a corresponding one of the time andlocation resources.
 2. The communication apparatus according to claim 1,wherein the data selection circuitry further acquires time informationindicating a current time, and, based on the location and travelingdirection information and the time information, selects the oneadvertisement candidate to be accepted for each of the time and locationresources in a future time.
 3. The communication apparatus according toclaim 1, wherein the data selection circuitry determines, depending onan installation location of the communication apparatus within thevehicle, the advertisement data to be transmitted by the transmissioncircuitry.
 4. The communication apparatus according to claim 1, whereinthe data selection circuitry incorporates, into the acquiredadvertisement data, ID information for identifying a radio base stationassociated with the communication apparatus.
 5. The communicationapparatus according to claim 1, wherein the acquired advertisement datais data for causing an advertisement to be displayed on a display ofeach of the plurality of mobile devices that receives the modulatedlight signal.
 6. The communication apparatus according to claim 1,wherein the transmission circuitry includes an illumination circuitconfigured to transmit the modulated light signal using a visible light.7. A communication method for a communication apparatus installed in avehicle, the communication method comprising: acquiring location andtraveling direction information of the vehicle in motion, selecting,based on the location and traveling direction information, oneadvertisement candidate related to a location ahead of a currentlocation of the vehicle in motion, wherein the one advertisementcandidate is selected from a plurality of advertisement candidates foreach of time and location resources defined by a time axis and alocation zone, acquiring advertisement data corresponding to theselected one advertisement candidate for each of the time and locationresources, wherein the advertisement data is different depending on thetime and location resource; and transmitting a modulated light signalthat includes the acquired advertisement data, the modulated lightsignal being for use by each of a plurality of mobile devices within thevehicle to display advertisement during a corresponding one of the timeand location resources.
 8. The communication method according to claim7, comprising: acquiring time information indicating a current time; andbased on the location and traveling direction information and the timeinformation, selecting the one advertisement candidate to be acceptedfor each of the time and location resources in a future time.
 9. Thecommunication method according to claim 7, comprising: determining,depending on an installation location of the communication apparatuswithin the vehicle, the advertisement data to be transmitted.
 10. Thecommunication method according to claim 7, comprising: incorporating,into the acquired advertisement data, ID information for identifying aradio base station associated with the communication apparatus.
 11. Thecommunication method according to claim 7, wherein the acquiredadvertisement data is data for causing an advertisement to be displayedon a display of each of the plurality of mobile devices that receivesthe modulated light signal.
 12. The communication method according toclaim 7, wherein the modulated light signal is a visible light.